A269014 Number of 4 X n binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two exactly once.
0, 48, 224, 2136, 10976, 73568, 390064, 2291728, 12190944, 67387784, 356115520, 1906181472, 9983123936, 52432319344, 272227610848, 1412208727736, 7276913394080, 37421599567712, 191604936958480, 978880041945808
Offset: 1
Keywords
Examples
Some solutions for n=4: ..0..0..1..0. .0..1..0..0. .0..1..0..0. .0..1..0..0. .1..0..0..0 ..0..1..0..0. .0..1..0..0. .1..0..0..0. .1..0..0..0. .0..0..1..0 ..0..0..0..1. .0..0..0..1. .0..0..0..1. .0..0..0..0. .1..0..1..0 ..0..1..0..0. .1..1..0..1. .1..0..0..1. .1..0..0..0. .1..0..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Row 4 of A269011.
Formula
Empirical: a(n) = 4*a(n-1) + 28*a(n-2) - 78*a(n-3) - 264*a(n-4) + 296*a(n-5) + 527*a(n-6) - 252*a(n-7) - 324*a(n-8).
Empirical g.f.: 8*x^2*(6 + 4*x - 13*x^2 - 12*x^3) / (1 - 2*x - 16*x^2 + 7*x^3 + 18*x^4)^2. - Colin Barker, Jan 18 2019