A259222 T(n,k) is the number of (n+1) X (k+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0000 0011 or 0101.
7, 13, 13, 24, 23, 24, 45, 40, 40, 45, 85, 71, 66, 71, 85, 162, 127, 112, 112, 127, 162, 311, 230, 192, 183, 192, 230, 311, 601, 421, 334, 303, 303, 334, 421, 601, 1168, 779, 588, 510, 487, 510, 588, 779, 1168, 2281, 1456, 1048, 869, 798, 798, 869, 1048, 1456, 2281
Offset: 1
Examples
Some solutions for n=4, k=4: 0 0 1 0 1 1 1 1 0 1 0 0 0 0 1 0 0 0 1 0 0 0 1 0 1 0 0 0 1 0 0 0 0 0 1 0 0 0 1 0 1 1 0 1 0 0 0 0 1 0 1 1 1 1 0 0 0 0 1 0 0 0 1 0 1 0 0 0 1 0 0 0 0 0 1 1 1 1 0 1 1 1 0 1 0 0 0 0 1 0 0 0 0 0 1 0 0 0 1 0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..480
Formula
Empirical for diagonal and column k (k=3..7 recurrences work also for k=1,2):
diagonal: a(n) = 6*a(n-1) - 10*a(n-2) - 2*a(n-3) + 16*a(n-4) - 6*a(n-5) - 5*a(n-6) + 2*a(n-7).
k=1: a(n) = 3*a(n-1) - a(n-2) - 2*a(n-3)
k=2: a(n) = 3*a(n-1) - a(n-2) - 2*a(n-3)
k=3: a(n) = 4*a(n-1) - 4*a(n-2) - a(n-3) + 2*a(n-4)
k=4: a(n) = 4*a(n-1) - 4*a(n-2) - a(n-3) + 2*a(n-4)
k=5: a(n) = 4*a(n-1) - 4*a(n-2) - a(n-3) + 2*a(n-4)
k=6: a(n) = 4*a(n-1) - 4*a(n-2) - a(n-3) + 2*a(n-4)
k=7: a(n) = 4*a(n-1) - 4*a(n-2) - a(n-3) + 2*a(n-4)
Comments