A183639 Number of (n+1) X 7 0..3 arrays with every 2 X 2 subblock summing to 6.

21016, 31060, 53512, 105604, 231736, 551380, 1398952, 3743524, 10479256, 30483700, 91664392, 283832644, 902755576, 2945024020, 9845481832, 33704772964, 118040932696, 422335788340, 1540872323272, 5720102724484, 21554302962616

Offset

1,1

Comments

Column 6 of A183642.

Links

R. H. Hardin, Table of n, a(n) for n = 1..77

Formula

Empirical: a(n) = 10*a(n-1) - 35*a(n-2) + 50*a(n-3) - 24*a(n-4).

Conjectures from Colin Barker, Mar 31 2018: (Start)

G.f.: 4*x*(5254 - 44775*x + 119618*x^2 - 98304*x^3) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)).

a(n) = 12138 + 483*2^(3+n) + 14*3^(3+n) + 4^(1+n).

(End)

Example

Some solutions for 3 X 7:
  0 0 1 3 1 2 3     3 2 3 3 0 0 1     3 0 1 0 3 1 3
  3 3 2 0 2 1 0     0 1 0 0 3 3 2     1 2 3 2 1 1 1
  0 0 1 3 1 2 3     3 2 3 3 0 0 1     2 1 0 1 2 2 2

Crossrefs

Cf. A183642.

Sequence in context: A344355 A231314 A157083 * A181260 A316482 A340897

Adjacent sequences: A183636 A183637 A183638 * A183640 A183641 A183642

Keyword

nonn

Author

R. H. Hardin, Jan 06 2011

Status

approved