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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.

A230649 Number of nX5 0..2 white 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 27
4 531
5 1635
6 28161
7 90393
8 1539207
9 4956927
10 84335553
11 271665969
12 4621740687
13 14888070495
14 253283346081
15 815905965057
16 13880597644287
17 44713811014239
18 760693546670625
19 2450435395047009
20 41688023124390687

List of values

[0, 15, 27, 531, 1635, 28161, 90393, 1539207, 4956927, 84335553, 271665969, 4621740687, 14888070495, 253283346081, 815905965057, 13880597644287, 44713811014239, 760693546670625, 2450435395047009, 41688023124390687]

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

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