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.

A204708 Number of (n+1) X 4 0..1 arrays with the permanents of all 2 X 2 subblocks equal and nonzero.

Table of values

n a(n)
1 25
2 81
3 257
4 833
5 2689
6 8705
7 28161
8 91137
9 294913
10 954369
11 3088385
12 9994241
13 32342017
14 104660993
15 338690049
16 1096024065
17 3546808321
18 11477712897
19 37142659073
20 120196169729
21 388962975745
22 1258710630401
23 4073273163777

List of values

[25, 81, 257, 833, 2689, 8705, 28161, 91137, 294913, 954369, 3088385, 9994241, 32342017, 104660993, 338690049, 1096024065, 3546808321, 11477712897, 37142659073, 120196169729, 388962975745, 1258710630401, 4073273163777]

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

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