A233073 T(n,k)=Number of nXk 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, antidiagonally or vertically, top left element zero, and 1 appearing before 2 in row major order.
1, 2, 2, 5, 9, 5, 14, 50, 50, 14, 41, 289, 582, 289, 41, 122, 1682, 6854, 6854, 1682, 122, 365, 9801, 80811, 164495, 80811, 9801, 365, 1094, 57122, 952869, 3957778, 3957778, 952869, 57122, 1094, 3281, 332929, 11235652, 95264272, 194998895, 95264272
Offset: 1
Examples
Some solutions for n=4 k=4 ..0..0..1..0....0..0..1..1....0..0..0..0....0..1..0..1....0..0..1..1 ..1..1..0..0....0..0..1..0....1..0..2..2....1..0..0..0....0..1..1..1 ..1..1..0..2....0..1..1..1....1..0..2..2....1..0..0..1....0..1..0..0 ..0..1..0..2....1..3..1..3....1..0..0..2....0..0..1..1....0..0..0..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..264
Formula
Empirical for column k:
k=1: a(n) = 4*a(n-1) -3*a(n-2)
k=2: a(n) = 7*a(n-1) -7*a(n-2) +a(n-3)
k=3: a(n) = 14*a(n-1) -28*a(n-2) +24*a(n-3) -11*a(n-4) +2*a(n-5) for n>6
k=4: [order 11] for n>12
k=5: [order 21] for n>23
k=6: [order 58] for n>60
Comments