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.

A381551 Number of 2*n X 4 binary arrays with row sums 2 and column sums n, avoiding the patterns 010 and 101 in any row and column.

Table of values

n a(n)
0 1
1 4
2 16
3 64
4 324
5 1764
6 10000
7 58564
8 350464
9 2131600
10 13133376
11 81757764
12 513294336
13 3245580900
14 20646241344
15 132021769104
16 848031024996
17 5468890936356
18 35392361925904
19 229761144199876
20 1495753923300484
21 9762043084514704
22 63858040015802256

List of values

[1, 4, 16, 64, 324, 1764, 10000, 58564, 350464, 2131600, 13133376, 81757764, 513294336, 3245580900, 20646241344, 132021769104, 848031024996, 5468890936356, 35392361925904, 229761144199876, 1495753923300484, 9762043084514704, 63858040015802256]

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

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