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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.
1
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
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: A126476 A220629 A377159 * A112908 A264819 A350128
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 17 2012
STATUS
approved