cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A232216 Number of non-isomorphic n X n nonnegative integer matrices with all row and column sums equal to 4 up to permutations of rows and columns.

Table of values

n a(n)
0 1
1 1
2 3
3 9
4 43
5 264
6 2804
7 44524
8 1012456
9 30502320
10 1166185222
11 54902972542
12 3115560948081
13 209575881782122
14 16484822517084705
15 1498893370236782629
16 155996155818460127750
17 18424063865105027559797
18 2450806855748517847761175
19 364738110721163795332103692
20 60368334488355648041244493885

List of values

[1, 1, 3, 9, 43, 264, 2804, 44524, 1012456, 30502320, 1166185222, 54902972542, 3115560948081, 209575881782122, 16484822517084705, 1498893370236782629, 155996155818460127750, 18424063865105027559797, 2450806855748517847761175, 364738110721163795332103692, 60368334488355648041244493885]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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