# oeis -- OEIS lookup

## Synopsis

• Optional inputs:
• Limit => ..., default value 100
• Position => ..., default value 0

## Description

This function looks up the argument (a list of integers or a string) in the Online Encyclopedia of Integer Sequences (http://oeis.org/).

 i1 : oeis {1,3,31,1145} o1 = {0 => (A029729 (see https://oeis.org/A029729 ) Degree of the variety of pairs of commuting n X n matrices.)} {1 => (A094579 (see https://oeis.org/A094579 ) Duplicate of A029729.) } o1 : NumberedVerticalList

Optional arguments Limit and Position allow to control the maximum amount of listed answers.

 i2 : L = apply(5,n->n!); i3 : oeis (L,Limit=>5) o3 = {0 => (A000142 (see https://oeis.org/A000142 ) Factorial numbers: n! = 1*2*3*4*...*n (order of symmetric group S_n, number of permutations of n letters).)} {1 => (A072856 (see https://oeis.org/A072856 ) Number of permutations satisfying i-4<=p(i)<=i+4, i=1..n (permutations of length n within distance 4).) } {2 => (A061602 (see https://oeis.org/A061602 ) Sum of factorials of the digits of n.) } {3 => (A177523 (see https://oeis.org/A177523 ) Number of permutations of 1..n avoiding adjacent step pattern up, up, up, up.) } {4 => (A263777 (see https://oeis.org/A263777 ) Number of inversion sequences avoiding pattern 201 (or 210).) } o3 : NumberedVerticalList i4 : oeis (L,Limit=>1,Position=>2) o4 = {0 => (A061602 (see https://oeis.org/A061602 ) Sum of factorials of the digits of n.)} o4 : NumberedVerticalList

## Ways to use oeis :

• "oeis(String)"
• "oeis(VisibleList)"

## For the programmer

The object oeis is .