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A252720
Number of (1+2) X (n+2) 0..3 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.
1
39, 52, 70, 96, 129, 175, 237, 319, 432, 584, 786, 1067, 1442, 1947, 2651, 3593, 4873, 6665, 9075, 12380, 17023, 23317, 32017, 44284, 61058, 84411, 117448, 163018, 226853, 317428, 443361, 620690, 872930, 1226059, 1725429, 2437194, 3439324
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 2*a(n-2) + 6*a(n-3) - a(n-4) - 11*a(n-5) - 12*a(n-6) + 5*a(n-7) + 20*a(n-8) + 8*a(n-9) - 8*a(n-10) - 12*a(n-11) + 4*a(n-13) for n>14.
Empirical g.f.: x*(39 + 52*x - 8*x^2 - 242*x^3 - 284*x^4 + 44*x^5 + 513*x^6 + 490*x^7 - 107*x^8 - 432*x^9 - 266*x^10 + 92*x^11 + 112*x^12 - 4*x^13) / ((1 - x)*(1 + x)*(1 - 2*x^3)^2*(1 - x^2 - 2*x^3 + x^5)). - Colin Barker, Dec 05 2018
EXAMPLE
Some solutions for n=4:
..0..1..1..2..2..0....0..1..0..1..1..0....0..1..0..0..2..2....0..1..0..0..2..2
..1..3..3..1..1..3....2..2..0..2..0..0....1..3..1..1..0..0....3..3..0..3..3..1
..2..0..0..3..3..2....3..3..0..0..2..0....2..2..3..3..1..3....1..0..0..1..0..0
CROSSREFS
Row 1 of A252719.
Sequence in context: A020305 A216978 A252719 * A070145 A133676 A317987
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2014
STATUS
approved