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A210119
Number of (n+1) X 3 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
44, 481, 5587, 67585, 836053, 10466659, 131849767, 1666227265, 21090849853, 267184911211, 3386189676751, 42924236694073, 544177325000245, 6899249896382995, 87473246343061879, 1109059012082436337
OFFSET
1,1
COMMENTS
Column 2 of A210125.
LINKS
FORMULA
Empirical: a(n) = 24*a(n-1) - 174*a(n-2) + 368*a(n-3) + 303*a(n-4) - 888*a(n-5) - 340*a(n-6) + 240*a(n-7).
Empirical g.f.: x*(44 - 575*x + 1699*x^2 + 999*x^3 - 4189*x^4 - 1510*x^5 + 1120*x^6) / ((1 - 6*x - 3*x^2 + 2*x^3)*(1 - 18*x + 69*x^2 - 10*x^3 - 120*x^4)). - Colin Barker, Jul 14 2018
EXAMPLE
Some solutions for n=4:
0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 0 1 1
0 1 0 0 1 0 0 1 0 0 1 1 1 0 1 2 3 1 2 3 3
0 1 1 2 3 2 2 3 2 1 1 0 1 0 0 0 1 1 3 2 2
2 3 3 1 0 1 0 1 0 0 0 0 0 0 1 3 2 1 2 2 0
0 1 1 1 0 0 2 3 2 0 1 0 0 1 0 2 2 1 1 1 3
CROSSREFS
Cf. A210125.
Sequence in context: A221730 A306036 A160150 * A272186 A222514 A282645
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 17 2012
STATUS
approved