A234732 Number of (n+1) X (2+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 8 (constant-stress 1 X 1 tilings).

672, 2184, 6048, 21048, 64320, 233016, 760608, 2827992, 9650112, 36532344, 128569248, 493143768, 1774812480, 6874544376, 25161581088, 98188573272, 364094768832, 1428934093944, 5353358809248, 21102161187288, 79707896139840

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 8*a(n-1) +53*a(n-2) -564*a(n-3) -888*a(n-4) +17184*a(n-5) -2382*a(n-6) -296784*a(n-7) +308859*a(n-8) +3196608*a(n-9) -5284083*a(n-10) -22169196*a(n-11) +48357478*a(n-12) +97763896*a(n-13) -273091508*a(n-14) -253071696*a(n-15) +976703832*a(n-16) +271829664*a(n-17) -2148744960*a(n-18) +304750080*a(n-19) +2640988800*a(n-20) -1133222400*a(n-21) -1378944000*a(n-22) +870912000*a(n-23).

Example

Some solutions for n=5:
 4 2 5   5 0 6   5 1 6   1 6 1   0 6 2   7 2 5   7 3 6
 0 6 1   3 6 4   3 7 4   4 1 4   4 2 6   4 7 2   3 7 2
 2 0 3   6 1 7   5 1 6   2 7 2   0 6 2   5 0 3   5 1 4
 0 6 1   2 5 3   0 4 1   5 2 5   2 0 4   3 6 1   1 5 0
 3 1 4   6 1 7   6 2 7   1 6 1   0 6 2   5 0 3   6 2 5
 1 7 2   1 4 2   2 6 3   5 2 5   3 1 5   3 6 1   3 7 2

Crossrefs

Column 2 of A234738.

Sequence in context: A233315 A157363 A308574 * A057805 A057796 A057797

Adjacent sequences: A234729 A234730 A234731 * A234733 A234734 A234735

Keyword

nonn

Author

R. H. Hardin, Dec 30 2013

Status

approved