A183645 Number of (n+1) X 3 0..4 arrays with every 2 X 2 subblock summing to 8.

325, 1001, 3445, 12785, 50125, 205001, 867205, 3771425, 16784125, 76156601, 351254965, 1642635665, 7771818925, 37132805801, 178875434725, 867570709505, 4231667890525, 20736710344601, 102006361694485, 503350999256945

Offset

1,1

Comments

Column 2 of A183652.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 15*a(n-1) - 85*a(n-2) + 225*a(n-3) - 274*a(n-4) + 120*a(n-5).

Empirical g.f.: x*(325 - 3874*x + 16055*x^2 - 26930*x^3 + 15000*x^4) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)). - Colin Barker, Apr 01 2018

Example

Some solutions for 5 X 3:
  1 2 1    0 3 0    3 1 2    0 4 0    2 2 2    2 2 2    4 1 1
  4 1 4    4 1 4    3 1 4    4 0 4    4 0 4    2 2 2    1 2 4
  1 2 1    3 0 3    1 3 0    2 2 2    1 3 1    0 4 0    3 2 0
  3 2 3    4 1 4    1 3 2    1 3 1    3 1 3    0 4 0    0 3 3
  2 1 2    0 3 0    4 0 3    1 3 1    1 3 1    1 3 1    3 2 0

Crossrefs

Cf. A183652.

Sequence in context: A351801 A160580 A158272 * A299708 A031714 A133447

Adjacent sequences: A183642 A183643 A183644 * A183646 A183647 A183648

Keyword

nonn

Author

R. H. Hardin, Jan 06 2011

Status

approved