Determines if a given number belongs to the Fibonacci sequence using `/v1/math/is-fibonacci`. Returns true/false with mathematical validation rather than guessing. Essential for sequence analysis in AI agents through MCP in Cursor or Windsurf, plus mathematical applications requiring precise Fibonacci identification.
curl "https://tinyfn.io/v1/math/is-fibonacci" \
-H "X-API-Key: YOUR_API_KEY"const response = await fetch('https://tinyfn.io/v1/math/is-fibonacci', {
headers: { 'X-API-Key': 'YOUR_API_KEY' }
});
const data = await response.json();
console.log(data);import requests
response = requests.get('https://tinyfn.io/v1/math/is-fibonacci',
headers={'X-API-Key': 'YOUR_API_KEY'})
data = response.json()
print(data)Connect your AI agent (Claude, Cursor, Windsurf, etc.) to TinyFn's math tools:
{
"mcpServers": {
"tinyfn-math": {
"url": "https://tinyfn.io/mcp/math",
"headers": {
"X-API-Key": "YOUR_API_KEY"
}
}
}
}Uses the mathematical property that n is Fibonacci if one of (5n²+4) or (5n²-4) is a perfect square.
Depends on implementation limits, but typically handles numbers up to JavaScript's MAX_SAFE_INTEGER (2^53-1).
Yes, zero is Fibonacci (F₀=0). Negative Fibonacci numbers exist in the extended sequence (negafibonacci).
AI agents can verify Fibonacci properties in code analysis, data validation, or mathematical proofs without calculating the entire sequence.
This validates membership without computation overhead—faster than generating sequences up to the target number.
Get your free API key and start using Is Fibonacci in seconds.
Get Free API Key