A301784 T(n,k)=Number of nXk 0..1 arrays with every element equal to 0, 1, 2 or 3 horizontally or vertically adjacent elements, with upper left element zero.
1, 2, 2, 4, 8, 4, 8, 32, 32, 8, 16, 128, 240, 128, 16, 32, 512, 1808, 1808, 512, 32, 64, 2048, 13616, 25872, 13616, 2048, 64, 128, 8192, 102544, 369936, 369936, 102544, 8192, 128, 256, 32768, 772272, 5289488, 10033408, 5289488, 772272, 32768, 256, 512, 131072
Offset: 1
Examples
Some solutions for n=5 k=4 ..0..0..0..0. .0..0..0..1. .0..0..0..0. .0..0..0..1. .0..0..0..0 ..0..1..0..1. .1..0..0..1. .0..1..1..1. .0..1..0..0. .0..0..1..1 ..0..1..1..0. .0..1..1..0. .0..1..1..0. .0..1..0..1. .0..1..1..1 ..1..0..1..1. .1..0..1..0. .1..0..0..1. .1..1..1..1. .0..1..0..0 ..0..0..0..0. .1..1..1..0. .1..1..1..0. .1..0..1..0. .0..0..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..364
Formula
Empirical for column k:
k=1: a(n) = 2*a(n-1)
k=2: a(n) = 4*a(n-1)
k=3: a(n) = 7*a(n-1) +4*a(n-2)
k=4: a(n) = 13*a(n-1) +20*a(n-2) -16*a(n-3) -64*a(n-4)
k=5: [order 8]
k=6: [order 20]
k=7: [order 46]
Comments