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.

A251221 Number of (n+1) X (1+1) 0..1 arrays with no 2 X 2 subblock having the minimum of its diagonal elements greater than the absolute difference of its antidiagonal elements.

Table of values

n a(n)
1 14
2 49
3 171
4 597
5 2084
6 7275
7 25396
8 88654
9 309479
10 1080349
11 3771351
12 13165272
13 45958169
14 160433700
15 560052166
16 1955065729
17 6824867819
18 23824682749
19 83168718156
20 290330652147
21 1013504710004
22 3538006716150
23 12350698916311

List of values

[14, 49, 171, 597, 2084, 7275, 25396, 88654, 309479, 1080349, 3771351, 13165272, 45958169, 160433700, 560052166, 1955065729, 6824867819, 23824682749, 83168718156, 290330652147, 1013504710004, 3538006716150, 12350698916311]

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

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