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.

A062156 Number of n X n matrices over {0,1,2} with all row and column sums equal to 1 or 2.

Table of values

n a(n)
0 1
1 2
2 13
3 189
4 4842
5 190080
6 10520010
7 777018690
8 73646397720
9 8696221929360
10 1249994376199800
11 214673857998276600
12 43377963701592920400
13 10180798532673708139200
14 2745082427076790292091600
15 842339587833332705318202000
16 291745985923439508815578224000

List of values

[1, 2, 13, 189, 4842, 190080, 10520010, 777018690, 73646397720, 8696221929360, 1249994376199800, 214673857998276600, 43377963701592920400, 10180798532673708139200, 2745082427076790292091600, 842339587833332705318202000, 291745985923439508815578224000]

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

Content is available under The OEIS End-User License Agreement.