Lucas number

lucas-number · version 1.0.0 · Numbers & math · free, no key needed

Compute the Lucas number at a zero-based index and return its exact decimal string.

Use when you need to: lucas number 90 · compute nth lucas number · exact lucas sequence value.

Decide before calling

Read the versioned contract and the supported scope below. Reuse lucas-number@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use lucas-number@1.0.0 for lucas number 90. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• lucas number 90
• compute nth lucas number
• exact lucas sequence value
• lucas number at index
• calculate lucas without rounding
• what is the 100th lucas number
• zero based lucas lookup

Not supported

• negative-index sequence extensions
• floating-point approximations
• unbounded sequence generation

Behavior

• L(0)=2, L(1)=1, and L(n)=L(n-1)+L(n-2).
• The index is zero-based and the result is an unsigned base-10 string.
• Standard version: OEIS A000032 (live entry retrieved 2026-11-05; NAME, initial terms, OFFSET 0,1); stable source URL: https://oeis.org/A000032.

Input

• index (integer, required): min 0; max 10000

Output

• index (integer, required): min 0; max 10000
• value (string, required): min length 1; max length 2091; pattern ^[0-9]+$
• standard_version (string, required): min length 1; max length 120

Limits

• max input bytes: 64
• max index: 10000
• max digits: 2091
• max iterations: 14
• max output bytes: 2300

Example

Request input:

{
  "index": 10
}

Response:

{
  "result": {
    "index": 10,
    "value": "123",
    "standard_version": "OEIS A000032 (live entry retrieved 2026-11-05; NAME, initial terms, OFFSET 0,1)"
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "lucas-number",
  "version": "1.0.0",
  "input": {
    "index": 10
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/lucas-number/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"index":10}'

The machine-readable contract is at /v1/tools/lucas-number/versions/1.0.0.

CLI

node cli.mjs run lucas-number 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

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