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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.

A203649 1/25 the number of (n+1) X (n+1) 0..4 arrays with every 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements.

Table of values

n a(n)
1 9
2 1517
3 1116249
4 3906948333
5 67213191427593
6 5796397762880763341

List of values

[9, 1517, 1116249, 3906948333, 67213191427593, 5796397762880763341]

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

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