A183630 Number of (n+1) X 8 0..2 arrays with every 2 X 2 subblock summing to 4.

7075, 8109, 10195, 14421, 23035, 40749, 77635, 155781, 325195, 703389, 1577875, 3681141, 8950555, 22678029, 59698915, 162438501, 454011115, 1295436669, 3753128755, 10993035861, 32446418875, 96273891309, 286690955395

Offset

1,1

Comments

Column 7 of A183632.

Links

R. H. Hardin, Table of n, a(n) for n = 1..149

Formula

Empirical: a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3).

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

G.f.: x*(7075 - 34341*x + 39366*x^2) / ((1 - x)*(1 - 2*x)*(1 - 3*x)).

a(n) = 6050 + 127*2^(2+n) + 3^(1+n).

(End)

Example

Some solutions for 3 X 8:
  0 0 1 2 1 1 2 1     1 2 1 1 1 1 2 0     0 2 0 2 0 0 0 2
  2 2 1 0 1 1 0 1     1 0 1 1 1 1 0 2     2 0 2 0 2 2 2 0
  0 0 1 2 1 1 2 1     1 2 1 1 1 1 2 0     0 2 0 2 0 0 0 2

Crossrefs

Cf. A183632.

Sequence in context: A063057 A235194 A034230 * A357478 A189354 A252383

Adjacent sequences: A183627 A183628 A183629 * A183631 A183632 A183633

Keyword

nonn

Author

R. H. Hardin, Jan 06 2011

Status

approved