A234734 Number of (n+1) X (4+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).

8736, 21048, 45792, 127032, 319488, 972888, 2723040, 8836536, 26699136, 90688728, 289595232, 1018007352, 3387971328, 12231257688, 42028017120, 154964007096, 546131550336, 2047907680728, 7365720907872, 27996112930872, 102364560941568

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=4:
  4 0 4 1 3      0 4 1 5 1      4 6 3 7 5      2 0 1 0 5
  1 5 1 6 0      5 1 6 2 6      6 0 5 1 7      1 7 0 7 4
  7 3 7 4 6      0 4 1 5 1      1 3 0 4 2      2 0 1 0 5
  2 6 2 7 1      6 2 7 3 7      6 0 5 1 7      1 7 0 7 4
  4 0 4 1 3      1 5 2 6 2      3 5 2 6 4      4 2 3 2 7

Crossrefs

Column 4 of A234738.

Sequence in context: A250999 A214171 A067867 * A250881 A234707 A257748

Adjacent sequences: A234731 A234732 A234733 * A234735 A234736 A234737

Keyword

nonn

Author

R. H. Hardin, Dec 30 2013

Status

approved