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A240382
Number of 2 X n 0..3 arrays with no element equal to zero plus the sum of elements to its left or two plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4.
1
4, 10, 38, 90, 366, 878, 3606, 8666, 35602, 85550, 351418, 844394, 3468498, 8334126, 34233910, 82257450, 337887294, 811877790, 3334934438, 8013202282, 32915673442, 79089995358, 324876418346, 780615181818, 3206517628418, 7704641519326
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 12*a(n-2) - 24*a(n-4) + 31*a(n-6) - 16*a(n-8).
Empirical g.f.: 2*x*(1 - x)*(2 + 7*x + 2*x^2 - 13*x^3 - 10*x^4 + 9*x^5 + 10*x^6) / (1 - 12*x^2 + 24*x^4 - 31*x^6 + 16*x^8). - Colin Barker, Oct 27 2018
EXAMPLE
Some solutions for n=4:
..3..1..3..1....3..1..3..1....1..3..1..3....1..3..1..3....3..1..3..1
..3..2..2..2....2..0..0..1....1..3..2..3....2..3..2..0....3..2..3..2
CROSSREFS
Row 2 of A240381.
Sequence in context: A102755 A197551 A046562 * A220198 A197051 A149191
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 04 2014
STATUS
approved