A300465 T(n,k)=Number of nXk 0..1 arrays with every element equal to 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
0, 0, 0, 0, 1, 0, 0, 2, 2, 0, 0, 4, 2, 4, 0, 0, 9, 8, 8, 9, 0, 0, 19, 22, 28, 22, 19, 0, 0, 41, 68, 142, 142, 68, 41, 0, 0, 88, 212, 540, 1146, 540, 212, 88, 0, 0, 189, 652, 2585, 7456, 7456, 2585, 652, 189, 0, 0, 406, 2017, 11343, 55663, 78195, 55663, 11343, 2017, 406, 0, 0
Offset: 1
Examples
Some solutions for n=5 k=4 ..0..0..0..0. .0..0..1..1. .0..0..1..1. .0..0..0..0. .0..0..0..0 ..0..1..0..0. .0..1..1..0. .0..0..1..1. .0..1..1..0. .0..1..0..0 ..1..1..1..1. .1..1..0..0. .1..1..0..0. .1..1..0..1. .1..1..1..1 ..1..0..1..1. .1..0..0..1. .1..0..0..1. .1..0..1..1. .0..0..0..1 ..0..0..1..1. .0..0..1..1. .1..1..1..1. .0..0..1..1. .0..0..1..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..220
Crossrefs
Column 2 is A078039(n-2).
Formula
Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = a(n-1) +2*a(n-2) +a(n-3)
k=3: [order 15]
k=4: [order 52] for n>54
Comments