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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.

A185820 1/5 the number of nX4 0..4 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Table of values

n a(n)
1 5
2 656
3 49036
4 4443292
5 378212944
6 32995092992
7 2852526229300
8 247462638659680
9 21440004040979204
10 1858466937288261508
11 161065823451839652032
12 13959918564726559991320
13 1209903218593886396425592

List of values

[5, 656, 49036, 4443292, 378212944, 32995092992, 2852526229300, 247462638659680, 21440004040979204, 1858466937288261508, 161065823451839652032, 13959918564726559991320, 1209903218593886396425592]

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

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