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oeis -- OEIS lookup

Synopsis

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 :

For the programmer

The object oeis is a method function with options.