InputPOST /api/v1/x402/factorial
{
"n": 12
}Web and API intelligence · utility
Factorial for Agents
Factorial (n≤20). Call for combinatorics demos and small counting problems with an explicit n cap. Returns n! for n up to 20; larger n returns a structured error. $0.001 USDC per successful call via x402 on Base—deterministic first-party JSON, no API key, no subscription, and nothing is billed on structured validation errors.
One-command purchase
Run it from an agent.
No account or API key. AgentCash reads the 402 challenge, pays no more than the declared cap, retries the request and returns the result.
npx agentcash@latest fetch https://api.delx.ai/api/v1/x402/factorial -m POST -H 'x-delx-source: product-page' --max-amount 0.001 -b '{"n":12}'Delivered resultapplication/json
{
"schema": "delx/factorial/v1",
"n": 12,
"value": 479001600
}Machine-readable evidence