A234817 Number of (n+1) X (2+1) 0..6 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6 (constant-stress 1 X 1 tilings).

686, 2220, 6282, 22098, 68570, 252486, 828354, 3136350, 10660586, 41107950, 143165922, 559043598, 1982378090, 7810154766, 28090231074, 111378700110, 405255972266, 1614238905870, 5930740315362, 23700937672398, 87799125560810

Offset

1,1

Links

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

Formula

Empirical: a(n) = 8*a(n-1) +60*a(n-2) -620*a(n-3) -1210*a(n-4) +20740*a(n-5) +1580*a(n-6) -392180*a(n-7) +353267*a(n-8) +4606324*a(n-9) -7135240*a(n-10) -34677440*a(n-11) +72387960*a(n-12) +165390560*a(n-13) -443380480*a(n-14) -464032320*a(n-15) +1696321584*a(n-16) +566607168*a(n-17) -3948347520*a(n-18) +465384960*a(n-19) +5084985600*a(n-20) -2142028800*a(n-21) -2757888000*a(n-22) +1741824000*a(n-23).

Example

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

Crossrefs

Column 2 of A234823.

Sequence in context: A116219 A232199 A222751 * A203459 A101944 A045150

Adjacent sequences: A234814 A234815 A234816 * A234818 A234819 A234820

Keyword

nonn

Author

R. H. Hardin, Dec 31 2013

Status

approved