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.

A269056 Number of 5Xn 0..2 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once.

Original entry on oeis.org

243, 2430, 17346, 183072, 1643376, 15547380, 140497512, 1273499256, 11354964888, 100764874440, 886829123676, 7765850889120, 67643548943508, 586749197487720, 5069733374448192, 43657996370224608, 374818434125094900
Offset: 1

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Author

R. H. Hardin, Feb 18 2016

Keywords

Comments

Row 5 of A269052.

Examples

			Some solutions for n=4
..0..1..2..1. .1..0..1..0. .0..1..2..1. .0..0..1..0. .1..1..0..0
..2..1..2..1. .0..0..1..2. .0..1..0..1. .1..2..1..2. .0..0..0..0
..2..1..0..2. .1..0..1..2. .0..1..2..1. .2..2..2..2. .0..0..0..1
..0..1..2..1. .0..0..1..0. .0..1..0..0. .2..1..2..1. .0..0..0..1
..0..1..2..2. .0..0..1..0. .0..0..0..0. .0..1..2..2. .1..0..0..1
		

Crossrefs

Cf. A269052.

Formula

Empirical: a(n) = 12*a(n-1) +26*a(n-2) -566*a(n-3) -123*a(n-4) +8804*a(n-5) -4121*a(n-6) -59620*a(n-7) +55115*a(n-8) +183692*a(n-9) -256127*a(n-10) -211910*a(n-11) +498819*a(n-12) -48036*a(n-13) -371692*a(n-14) +214008*a(n-15) +43848*a(n-16) -64656*a(n-17) +8640*a(n-18) +5184*a(n-19) -1296*a(n-20) for n>22