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.

A222511 Number of 3Xn 0..1 arrays with exactly floor(3Xn/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Table of values

n a(n)
1 0
2 4
3 4
4 15
5 35
6 170
7 441
8 2192
9 5416
10 26660
11 66209
12 328121
13 816736
14 4074688
15 10172187
16 51053330
17 127212627
18 643151980
19 1598614930
20 8135779154
21 20183768037
22 103256080822
23 255983883834
24 1314494576457
25 3259213240495
26 16780895442470

List of values

[0, 4, 4, 15, 35, 170, 441, 2192, 5416, 26660, 66209, 328121, 816736, 4074688, 10172187, 51053330, 127212627, 643151980, 1598614930, 8135779154, 20183768037, 103256080822, 255983883834, 1314494576457, 3259213240495, 16780895442470]

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

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