Fibonacci sequence

fibonacci-sequence · version 1.0.0 · Numbers & math · free, no key needed

List exact Fibonacci numbers for an inclusive zero-based index range as decimal strings.

Use when you need to: list fibonacci numbers · fibonacci sequence range · fibonacci numbers between indices.

Decide before calling

Read the versioned contract and the supported scope below. Reuse fibonacci-sequence@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 fibonacci-sequence@1.0.0 for list fibonacci numbers. 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

• list fibonacci numbers
• fibonacci sequence range
• fibonacci numbers between indices
• generate first fibonacci values
• bounded fibonacci sequence
• fibonacci list from index to index
• exact fibonacci series

Not supported

• unbounded Fibonacci streams
• Lucas number ranges
• negative or fractional indices

Behavior

• The inclusive range returns F(start_index) through F(end_index), where F(0)=0 and F(1)=1.
• Ranges contain 1 through 100 items; values are unsigned base-10 strings in ascending index order.
• Standard version: OEIS A000045 (live entry retrieved 2026-11-05; NAME, initial terms, OFFSET 0,4); stable source URL: https://oeis.org/A000045.

Input

• start_index (integer, required): min 0; max 5000
• end_index (integer, required): min 0; max 5000

Output

• start_index (integer, required): min 0; max 5000
• end_index (integer, required): min 0; max 5000
• values (array of string, required): min items 1; max items 100; each min length 1; each max length 1045; each pattern ^[0-9]+$
• standard_version (string, required): min length 1; max length 120

Limits

• max input bytes: 96
• max index: 5000
• max items: 100
• max digits per item: 1045
• max iterations: 1400
• max output bytes: 112000

Example

Request input:

{
  "start_index": 0,
  "end_index": 7
}

Response:

{
  "result": {
    "start_index": 0,
    "end_index": 7,
    "values": [
      "0",
      "1",
      "1",
      "2",
      "3",
      "5",
      "8",
      "13"
    ],
    "standard_version": "OEIS A000045 (live entry retrieved 2026-11-05; NAME, initial terms, OFFSET 0,4)"
  }
}

How to call it

MCP

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

{
  "id": "fibonacci-sequence",
  "version": "1.0.0",
  "input": {
    "start_index": 0,
    "end_index": 7
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/fibonacci-sequence/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"start_index":0,"end_index":7}'

The machine-readable contract is at /v1/tools/fibonacci-sequence/versions/1.0.0.

CLI

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

Get the client at /clients/cli/.

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