A240039 T(n,k)=Number of nXk 0..2 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 3.
2, 2, 2, 4, 2, 4, 4, 6, 6, 4, 8, 4, 16, 4, 8, 8, 10, 16, 16, 10, 8, 16, 8, 42, 18, 42, 8, 16, 16, 20, 44, 52, 52, 44, 20, 16, 32, 16, 114, 62, 154, 62, 114, 16, 32, 32, 40, 122, 162, 178, 178, 162, 122, 40, 32, 64, 32, 314, 204, 494, 282, 494, 204, 314, 32, 64, 64, 80, 340, 530, 600
Offset: 1
Examples
Some solutions for n=3 k=4 ..2..1..1..2....2..1..2..1....2..1..2..1....1..2..1..2....1..2..1..2 ..1..0..0..0....1..0..0..0....1..0..0..0....2..0..0..0....2..0..0..0 ..1..0..0..0....1..0..0..0....2..0..0..0....2..0..0..0....2..0..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..511
Formula
Empirical for column k:
k=1: a(n) = 2*a(n-2)
k=2: a(n) = 2*a(n-2) for n>5
k=3: a(n) = 4*a(n-2) -3*a(n-4) -a(n-6) for n>7
k=4: [order 24] for n>27
k=5: [order 86] for n>89
Comments