Exact combinatorics with big integers
Exact combinatorics with big integers - factorial, nPr, nCr, combinations with repetition, derangements and Catalan numbers for n up to 2000
Answeringour last check, 2026-10-20
1 of 1checks answered this week
287 msmedian answer time
$0.01listed price per call
$0.01price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://saylorinnovations.com/api/math/combinatorics
| Category | Everything else |
|---|---|
| Provider host | saylorinnovations.com |
| Networks | eip155:137, eip155:42161, eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp |
| Payment schemes | exact |
| Self-reported calls, 30 days | 0 from 0 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-20 | valid payment request | 402 | $0.01 | 287 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"n": "52",
"r": "5"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"n": {
"description": "Integer 0-2000",
"type": "string"
},
"r": {
"description": "optional integer for nPr and nCr",
"type": "string"
}
},
"required": [
"n"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"arrangements_with_repetition": {
"description": "Arrangements with repetition",
"type": [
"string",
"null"
]
},
"catalan": {
"description": "n-th Catalan number",
"type": [
"string",
"null"
]
},
"combinations_nCr": {
"description": "Combinations n cr",
"type": "string"
},
"combinations_scientific": {
"description": "Combinations scientific",
"type": [
"string",
"null"
]
},
"combinations_with_repetition": {
"description": "Combinations with repetition",
"type": "string"
},
"derangements": {
"description": "Permutations with no fixed point",
"type": [
"string",
"null"
]
},
"factorial": {
"description": "n factorial as an exact integer",
"type": "string"
},
"factorial_digits": {
"description": "Factorial digits",
"type": "number"
},
"factorial_scientific": {
"description": "Factorial scientific",
"type": "string"
},
"n": {
"description": "Number of items",
"type": "number"
},
"permutations_nPr": {
"description": "Permutations n pr",
"type": "string"
},
"permutations_scientific": {
"description": "Permutations scientific",
"type": [
"string",
"null"
]
},
"r": {
"description": "Number chosen",
"type": "number"
},
"source": {
"description": "Data source the values come from",
"type": "string"
}
},
"required": [
"n",
"factorial"
],
"type": "object"
},
"type": {
"const": "json",
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}