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.

A222899 Number of n X n 0..3 arrays with no more than floor(n X n/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order.

Table of values

n a(n)
1 1
2 4
3 45
4 7794
5 2117424
6 10615237672
7 51666240687220
8 4291633334520814783
9 347033965049827951084160

List of values

[1, 4, 45, 7794, 2117424, 10615237672, 51666240687220, 4291633334520814783, 347033965049827951084160]

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

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