A234660 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 4 (constant-stress 1 X 1 tilings).

1820, 9774, 52646, 286668, 1566596, 8659270, 48048220, 269752200, 1520415050, 8671291020, 49644175568, 287539714338, 1671300725440, 9823825117164, 57918470971102, 345126319941768, 2061436669618116, 12436683541246942

Offset

1,1

Links

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

Formula

Empirical: a(n) = 24*a(n-1) -116*a(n-2) -1573*a(n-3) +17655*a(n-4) -7512*a(n-5) -599532*a(n-6) +2201681*a(n-7) +4899218*a(n-8) -40315144*a(n-9) +38576320*a(n-10) +130316460*a(n-11) -132305400*a(n-12) -263116800*a(n-13) +8496000*a(n-14) +134568000*a(n-15) +45360000*a(n-16).

Example

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

Crossrefs

Column 2 of A234665.

Sequence in context: A353807 A326236 A156636 * A238030 A233719 A174770

Adjacent sequences: A234657 A234658 A234659 * A234661 A234662 A234663

Keyword

nonn

Author

R. H. Hardin, Dec 29 2013

Status

approved