A234722 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 7 (constant-stress 1 X 1 tilings).

1096, 3976, 12464, 48976, 168928, 692512, 2531888, 10649920, 40456096, 173104096, 675830384, 2926809856, 11669180128, 50984087392, 206719128368, 909199934080, 3737628522016, 16522547685856, 68705695864304, 304909972231936

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +137*a(n-2) -560*a(n-3) -8456*a(n-4) +35504*a(n-5) +310702*a(n-6) -1349320*a(n-7) -7561533*a(n-8) +34294092*a(n-9) +128206281*a(n-10) -615707400*a(n-11) -1548288698*a(n-12) +8040276992*a(n-13) +13333179376*a(n-14) -77453548480*a(n-15) -79946374816*a(n-16) +552146144704*a(n-17) +309222145232*a(n-18) -2893327015040*a(n-19) -567224779296*a(n-20) +10948880162304*a(n-21) -974085452928*a(n-22) -28950298675200*a(n-23) +9103597862400*a(n-24) +50436504576000*a(n-25) -24908850432000*a(n-26) -51674112000000*a(n-27) +32903055360000*a(n-28) +23410114560000*a(n-29) -17557585920000*a(n-30).

Example

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

Crossrefs

Column 2 of A234728.

Sequence in context: A163561 A203807 A184470 * A160370 A123366 A186476

Adjacent sequences: A234719 A234720 A234721 * A234723 A234724 A234725

Keyword

nonn

Author

R. H. Hardin, Dec 30 2013

Status

approved