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.

A280434 Number of n X n 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

Table of values

n a(n)
1 0
2 4
3 21
4 80
5 225
6 548
7 1211
8 2512
9 4989
10 9604
11 18073
12 33432
13 61035
14 110276
15 197581
16 351568
17 621945

List of values

[0, 4, 21, 80, 225, 548, 1211, 2512, 4989, 9604, 18073, 33432, 61035, 110276, 197581, 351568, 621945]

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

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