A233026 T(n,k)=Number of nXk 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, vertically, diagonally or antidiagonally, and top left element zero.
1, 3, 3, 9, 15, 9, 27, 81, 81, 27, 81, 435, 849, 435, 81, 243, 2337, 8835, 8835, 2337, 243, 729, 12555, 92067, 179999, 92067, 12555, 729, 2187, 67449, 959385, 3685017, 3685017, 959385, 67449, 2187, 6561, 362355, 9997413, 75489671, 149128385
Offset: 1
Examples
Some solutions for n=4 k=4 ..0..2..2..2....0..0..2..2....0..0..0..2....0..0..0..1....0..0..0..2 ..2..0..0..2....2..2..0..0....0..2..0..0....0..0..0..1....2..2..2..2 ..2..2..0..0....2..2..0..0....0..2..2..2....0..1..1..1....2..2..0..0 ..2..2..2..0....0..0..0..0....2..2..0..0....0..0..0..0....2..2..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..264
Crossrefs
Column 1 is A000244(n-1)
Formula
Empirical for column k:
k=1: a(n) = 3*a(n-1)
k=2: a(n) = 5*a(n-1) +2*a(n-2)
k=3: a(n) = 11*a(n-1) -5*a(n-2) -11*a(n-3) +2*a(n-4)
k=4: [order 8]
k=5: [order 20]
k=6: [order 50]
Comments