A210118 Number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having two or four distinct values, and new values 0..3 introduced in row major order.

8, 44, 265, 1702, 11369, 77642, 536581, 3731446, 26032433, 181914722, 1272290749, 8902073710, 62300406761, 436052596634, 3052189205941, 21364687028710, 149550539021345, 1046845687784786, 7327891018040365, 51295134566193886

Offset

1,1

Comments

Column 1 of A210125.

Links

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

Formula

Empirical: a(n) = 10*a(n-1) - 19*a(n-2) - 14*a(n-3).

Empirical g.f.: x*(8 - 36*x - 23*x^2) / ((1 - 7*x)*(1 - 3*x - 2*x^2)). - Colin Barker, Jul 14 2018

Example

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

Crossrefs

Cf. A210125.

Sequence in context: A155604 A126476 A220629 * A112908 A264819 A350128

Adjacent sequences: A210115 A210116 A210117 * A210119 A210120 A210121

Keyword

nonn

Author

R. H. Hardin, Mar 17 2012

Status

approved