A302368 Number of 2Xn 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
2, 2, 12, 20, 72, 168, 496, 1296, 3616, 9760, 26816, 73024, 199808, 545408, 1490688, 4071680, 11125248, 30392832, 83037184, 226857984, 619792384, 1693296640, 4626182144, 12638949376, 34530271232, 94338424832, 257737408512
Offset: 1
Keywords
Examples
Some solutions for n=5 ..0..1..0..1..0. .0..0..0..0..1. .0..1..1..1..0. .0..0..1..0..1 ..0..1..0..1..0. .1..0..1..0..0. .1..1..0..1..1. .0..0..0..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A302367.
Formula
Empirical: a(n) = 2*a(n-1) +4*a(n-2) -4*a(n-3) -4*a(n-4)
Comments