Combinatorics

An MCP tool from the Calculators server, hosted on mcp.hjlabs.in.

Exact factorial, combinations nCr, permutations nPr, and combinations with repetition, for n up to 5000 (BigInt, no rounding).

Name on the gateway: math__combinatorics · read-only.

Parameters

Name	Type	Description
`n` required	`integer`	Number of items, 0–5000.
`r`	`integer`	Number chosen. Needed for everything except factorial.
`kind`	`all \| factorial \| combinations \| permutations \| multiset`	Default "all".

Through the Smart Gateway, any client can run it by name with call_tool, or let the gateway find it with search_tools:

call_tool arguments

{
  "name": "math__combinatorics",
  "arguments": {
    "n": 0
  }
}

Or connect the Calculators server directly, which lists 28 tools including this one:

Run in your terminal

claude mcp add --transport http hj-math https://mcp.hjlabs.in/mcp/math \
  --header "Authorization: Bearer YOUR_API_KEY"

Use the combinatorics tool with n set to ….