Evidence row 1920

Observed 26 Oct 2026, 14:34 UTC, by baseline/1.

Kind: listing
About: source_record agentic_market:combinatorics-openverbs-com
Recorded: 26 Oct 2026, 14:34 UTC
Previous row: None: the first of its kind about this subject
Body SHA-256: 2837f6f2ebda6e730f4c16b9a7b56cc2b97c4e941343a80b391dc2d619341635
Leaf: 0xfdf681d72e055ee969a9f5e0a1aedbe6bae3caef2135713373d4e4fe6986949d

What was observed

{
  "endpoints": [
    [
      "x402",
      "https://combinatorics.openverbs.com/v1/catalan"
    ],
    [
      "x402",
      "https://combinatorics.openverbs.com/v1/combinations"
    ],
    [
      "x402",
      "https://combinatorics.openverbs.com/v1/factorial"
    ],
    [
      "x402",
      "https://combinatorics.openverbs.com/v1/multinomial"
    ],
    [
      "x402",
      "https://combinatorics.openverbs.com/v1/permutations"
    ]
  ],
  "name": "combinatorics.openverbs.com",
  "owner_address": null,
  "raw": {
    "caip2_networks": [
      "eip155:8453"
    ],
    "category": "",
    "description": "",
    "domain": "combinatorics.openverbs.com",
    "endpoints": [
      {
        "description": "The n-th Catalan number Cₙ = C(2n, n)/(n+1), counting balanced bracketings, binary trees, and many other structures. Requires n ≤ 10000.",
        "method": "POST",
        "parameters": [
          {
            "default": null,
            "description": "",
            "enumValues": [],
            "example": "42",
            "group": "body",
            "name": "n",
            "required": false,
            "type": "string"
          }
        ],
        "pricing": {
          "amount": "0.004",
          "currency": "USDC",
          "maxAmount": "",
          "minAmount": "",
          "network": "eip155:8453",
          "scheme": "exact"
        },
        "providerName": "",
        "quality": {
          "l30DaysTotalCalls": "2",
          "l30DaysUniquePayers": "2"
        },
        "serviceName": "Catalan number",
        "tags": [
          "catalan number",
          "compute catalan",
          "balanced bracket count",
          "binary tree count",
          "catalan api"
        ],
        "url": "https://combinatorics.openverbs.com/v1/catalan"
      },
      {
        "description": "Binomial coefficient nCr = n!/(r!(n-r)!), the number of unordered r-subsets of n. Requires r ≤ n and min(r, n-r) ≤ 10000.",
        "method": "POST",
        "parameters": [
          {
            "default": null,
            "description": "",
            "enumValues": [],
            "example": "42",
            "group": "body",
            "name": "n",
            "required": false,
            "type": "string"
          },
          {
            "default": null,
            "description": "",
            "enumValues": [],
            "example": "42",
            "group": "body",
            "name": "r",
            "required": false,
            "type": "string"
          }
        ],
        "pricing": {
          "amount": "0.004",
          "currency": "USDC",
          "maxAmount": "",
          "minAmount": "",
          "network": "eip155:8453",
          "scheme": "exact"
        },
        "providerName": "",
        "quality": {
          "l30DaysTotalCalls": "2",
          "l30DaysUniquePayers": "2"
        },
        "serviceName": "Combinations (nCr)",
        "tags": [
          "combinations ncr",
          "compute combinations",
          "binomial coefficient",
          "ncr api",
          "choose r from n"
        ],
        "url": "https://combinatorics.openverbs.com/v1/combinations"
      },
      {
        "description": "Exact factorial n! for 0 ≤ n ≤ 20000, returned as a decimal string with its digit count.",
        "method": "POST",
        "parameters": [
          {
            "default": null,
            "description": "",
            "enumValues": [],
            "example": "42",
            "group": "body",
            "name": "n",
            "required": false,
            "type": "string"
          }
        ],
        "pricing": {
          "amount": "0.004",
          "currency": "USDC",
          "maxAmount": "",
          "minAmount": "",
          "network": "eip155:8453",
          "scheme": "exact"
        },
        "providerName": "",
        "quality": {
          "l30DaysTotalCalls": "1",
          "l30DaysUniquePayers": "1"
        },
        "serviceName": "Factorial",
        "tags": [
          "factorial api",
          "compute factorial",
          "n factorial",
          "exact factorial",
          "bigint factorial"
        ],
        "url": "https://combinatorics.openverbs.com/v1/factorial"
      },
      {
        "description": "Multinomial coefficient (k1+k2+…)! / (k1! k2! …) — the number of ways to partition n = Σki items into labelled groups of the given sizes. The sum must be ≤ 20000.",
        "method": "POST",
        "parameters": [
          {
            "default": null,
            "description": "",
            "enumValues": [],
            "example": [],
            "group": "body",
            "name": "groups",
            "required": false,
            "type": "array"
          }
        ],
        "pricing": {
          "amount": "0.004",
          "currency": "USDC",
          "maxAmount": "",
          "minAmount": "",
          "network": "eip155:8453",
          "scheme": "exact"
        },
        "providerName": "",
        "quality": {
          "l30DaysTotalCalls": "1",
          "l30DaysUniquePayers": "1"
        },
        "serviceName": "Multinomial coefficient",
        "tags": [
          "multinomial coefficient",
          "compute multinomial",
          "partition items into groups",
          "labelled group count",
          "multinomial api"
        ],
        "url": "https://combinatorics.openverbs.com/v1/multinomial"
      },
      {
        "description": "Number of ordered arrangements of r items from n, nPr = n!/(n-r)!. Requires r ≤ n and r ≤ 10000.",
        "method": "POST",
        "parameters": [
          {
            "default": null,
            "description": "",
            "enumValues": [],
            "example": "42",
            "group": "body",
            "name": "n",
            "required": false,
            "type": "string"
          },
          {
            "default": null,
            "description": "",
            "enumValues": [],
            "example": "42",
            "group": "body",
            "name": "r",
            "required": false,
            "type": "string"
          }
        ],
        "pricing": {
          "amount": "0.004",
          "currency": "USDC",
          "maxAmount": "",
          "minAmount": "",
          "network": "eip155:8453",
          "scheme": "exact"
        },
        "providerName": "",
        "quality": {
          "l30DaysTotalCalls": "1",
          "l30DaysUniquePayers": "1"
        },
        "serviceName": "Permutations (nPr)",
        "tags": [
          "permutations npr",
          "compute permutations",
          "ordered arrangements",
          "npr api",
          "permutation count"
        ],
        "url": "https://combinatorics.openverbs.com/v1/permutations"
      }
    ],
    "enriched": false,
    "iconUrl": "",
    "id": "combinatorics-openverbs-com",
    "integrationType": "",
    "isNew": false,
    "name": "combinatorics.openverbs.com",
    "networks": [
      "Base"
    ],
    "priceSummary": {
      "avgCostBasis": "exact",
      "avgCostPerTransaction": "0.004",
      "currency": "USDC",
      "maxAmount": "0.004",
      "minAmount": "0.004"
    },
    "provider": "combinatorics.openverbs.com",
    "providerUrl": "",
    "serviceName": "",
    "tags": [
      "catalan number",
      "compute catalan",
      "balanced bracket count",
      "binary tree count",
      "catalan api",
      "combinations ncr",
      "compute combinations",
      "binomial coefficient",
      "ncr api",
      "choose r from n",
      "factorial api",
      "compute factorial",
      "n factorial",
      "exact factorial",
      "bigint factorial",
      "multinomial coefficient",
      "compute multinomial",
      "partition items into groups",
      "labelled group count",
      "multinomial api",
      "permutations npr",
      "compute permutations",
      "ordered arrangements",
      "npr api",
      "permutation count"
    ]
  },
  "source": "agentic_market",
  "summary": ""
}

What the leaf hashes

{"body":"2837f6f2ebda6e730f4c16b9a7b56cc2b97c4e941343a80b391dc2d619341635","id":1920,"kind":"listing","method":"baseline/1","observed_us":1793025259616359,"prev":null,"subject":"agentic_market:combinatorics-openverbs-com","subject_kind":"source_record"}

Proof

Fold these into the leaf in order, hashing each sorted pair with keccak256, to reach the root of 2026-10-26 (296695 rows).

0xfdf66334da028864a1ab2bb7fbb96f52fe395670681bc1c59a37cbd77ce71242
0x6b17efec268cc00a7df5ff5d3fec666848c9dfe893c44933f192f9a067727483
0xa7f84e29efae9392e97889f2571beb2d58ae6125d62e0ac2081fdc37e8b668bd
0xb9eb71b54ba10ad070f16694513b5643f64b89f917687906a7f23691419d9663
0xbe64496e8420e0d4a1d1270e4df36eeeec52f6ed3e4d7ad2e4a11b8fc297b26d
0x12a0aa415f76cb09ca7e09b15dcfccab1501d9b14e60a90cf13700152303bd2b
0x13de11aecaee7f58fd90c4f486eac681a4dd6b71d54c5c8055ef7a1bb0c8a7d6
0xe8b6050f58737969d73be4e74d11527ea079ef5be9ab0d67dee54c78ae452f3a
0xe297f8a98feeb35fea558eda8f305d2c9d12515dc34140be597827a50527f0e0
0x8420578b5ff109895e07c3ba27d964c26e4280e809929d899076e79b5c159eaf
0xf45641bf26b2b86d9338aa6dc8640a8a378fbd786d23400636aaf30709453e50
0xa1d268c111b09550fdb70b6d9d0b58c94dc828b083baa8f1360300aab6230a9c
0xbee644d57738676bfb20eb90d6021f364bf883a8d54f8d17e9dc4749b4074c3d
0x44945ea9ad8b24e723ad5a8fd6d014024a49531783f74ff9229c2ab6930e84c8
0x68d296b1e00b4899fb83c3fba36fffaefa311eac2903067dbebfe776a12b4a9a
0x5fb5dda563336cd1bc1b9f44c52b76237ae72ed2145cb9290f39f304ca7dd678
0x74a0a08e4e7ab9aa5bfbead33dec7e1c7e8e364cff69a63720d764bbe987aadc

Day root: 0xf43e8dcc3d451a4788b26be904c55e8c4c0fa75c9666796c51db38d37e2c0df8
Chained: 0x702d5ac508f08b0d1accf36af25822d8e5660367494edd17a642fb61e158a57a
Published: On Arc Testnet, block 69251483: 0x495162f8936e19f0039918feebe6c307f327cd6bf8c37219620b1970041fa9ae

How to check it · This row as JSON