A269143 T(n,k)=Number of nXk 0..3 arrays with some element plus some horizontally, antidiagonally or vertically adjacent neighbor totalling three no more than once.
4, 16, 16, 60, 148, 60, 216, 1164, 1164, 216, 756, 8532, 18556, 8532, 756, 2592, 59916, 275796, 275796, 59916, 2592, 8748, 408596, 3924212, 8317996, 3924212, 408596, 8748, 29160, 2727564, 54199284, 240647068, 240647068, 54199284, 2727564, 29160
Offset: 1
Examples
Some solutions for n=3 k=4 ..0..3..2..3. .2..0..2..2. .0..0..0..2. .0..3..2..3. .0..2..2..2 ..2..3..2..2. .2..0..0..0. .0..0..0..2. .2..3..3..3. .0..0..0..2 ..2..2..3..3. .3..1..0..2. .1..1..0..1. .2..2..2..2. .0..2..2..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..220
Crossrefs
Column 1 is A120926(n+1).
Formula
Empirical for column k:
k=1: a(n) = 6*a(n-1) -9*a(n-2)
k=2: a(n) = 12*a(n-1) -38*a(n-2) +12*a(n-3) -a(n-4) for n>5
k=3: [order 8] for n>9
k=4: [order 20] for n>22
k=5: [order 42] for n>45
Comments