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A241055
Number of 2 X n 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.
1
2, 3, 2, 10, 18, 18, 46, 58, 102, 173, 264, 487, 738, 1318, 2151, 3591, 6192, 10096, 17480, 28925, 49131, 82966, 138977, 236535, 395979, 671706, 1131018, 1908201, 3226558, 5432423, 9189152, 15486612, 26156656, 44151446, 74485403, 125808822
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-2) + 3*a(n-3) - 3*a(n-4) - 4*a(n-5) - 2*a(n-6) + 3*a(n-7) - a(n-9) + 2*a(n-11) - 2*a(n-12) + 2*a(n-15) for n>17.
Empirical g.f.: x*(2 + 3*x - 4*x^2 - 5*x^3 + 9*x^4 - x^5 - 16*x^6 - 12*x^7 - x^8 + 3*x^9 + 3*x^10 + 11*x^12 - 10*x^13 - 8*x^14 + 6*x^15 + 8*x^16) / ((1 - x)*(1 + x - 2*x^2 - 5*x^3 - 2*x^4 + 2*x^5 + 4*x^6 + x^7 + x^8 + 2*x^9 + 2*x^10 + 2*x^12 + 2*x^13 + 2*x^14)). - Colin Barker, Oct 29 2018
EXAMPLE
Some solutions for n=4:
..3..3..2..2....3..3..2..2....3..2..3..3....3..2..3..3....3..3..2..2
..2..1..1..3....2..2..0..0....2..1..1..0....2..1..1..2....2..2..0..3
CROSSREFS
Row 2 of A241054.
Sequence in context: A333129 A078828 A247170 * A224418 A220947 A224417
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 15 2014
STATUS
approved