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.

A230659 Number of n X 5 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j).

Table of values

n a(n)
1 0
2 15
3 135
4 531
5 8613
6 28161
7 477279
8 1539207
9 26178201
10 84335553
11 1434726783
12 4621740687
13 78627215025
14 253283346081
15 4308981442911
16 13880597644287
17 236143613924865
18 760693546670625
19 12941296146524511
20 41688023124390687

List of values

[0, 15, 135, 531, 8613, 28161, 477279, 1539207, 26178201, 84335553, 1434726783, 4621740687, 78627215025, 253283346081, 4308981442911, 13880597644287, 236143613924865, 760693546670625, 12941296146524511, 41688023124390687]

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

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