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.

A297509 Number of 4Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 2 neighboring 1s.

Table of values

n a(n)
1 1
2 87
3 531
4 2281
5 23348
6 191192
7 1247716
8 9450219
9 74086027
10 542295341
11 4014135733
12 30366147431
13 226985241429
14 1690164545942
15 12658565659102
16 94748613114792
17 707806468257951
18 5292426347783239
19 39588593164337549

List of values

[1, 87, 531, 2281, 23348, 191192, 1247716, 9450219, 74086027, 542295341, 4014135733, 30366147431, 226985241429, 1690164545942, 12658565659102, 94748613114792, 707806468257951, 5292426347783239, 39588593164337549]