Usage Guide

This guide covers the core functionalities of oeis-code.

Getting Sequence Terms

The primary interface is the get() function. It evaluates the sequence at a given index.

from oeis_code import get

# Get the 10th Fibonacci number
val = get("A000045", 10)
print(val) # 55

Adding Sequences

To add sequences to oeis-code, you register them in the src/oeis_code/sequences/ directory:

from oeis_code.registry import register

@register("A000045")
def sequence(n):
    if n <= 1:
        return n
    return sequence(n - 1) + sequence(n - 2)

Backends

oeis-code provides fallbacks and PARI/GP bindings for high performance sequence calculations. Ensure you have pari-gp installed on your system to take advantage of the advanced cypari2 backend.