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URL: https://oeis.org/A202256

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A202256
Number of zero-sum -n..n arrays of 6 elements with adjacent element differences also in -n..n.
1
33, 387, 2003, 6963, 18841, 43293, 88301, 164873, 287151, 473293, 745359, 1130441, 1660283, 2372685, 3310839, 4525059, 6071723, 8015439, 10427561, 13388757, 16987109, 21321159, 26497455, 32634197, 39858185, 48309035, 58135563, 69500619, 82576757, 97551845, 114623981
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 2*a(n-2) +2*a(n-3) -3*a(n-5) -3*a(n-6) -2*a(n-7) +a(n-8) +4*a(n-9) +4*a(n-10) +a(n-11) -2*a(n-12) -3*a(n-13) -3*a(n-14) +2*a(n-16) +2*a(n-17) -a(n-19).
Empirical g.f.: -x*(-33 -387*x -1937*x^2 -6123*x^3 -14061*x^4 -25460*x^5 -37953*x^6 -47841*x^7 -51602*x^8 -47844*x^9 -37956*x^10 -25461*x^11 -14061*x^12 -6120*x^13 -1935*x^14 -387*x^15 -35*x^16 -x^17+x^18) / ( (x^2+1) *(x^4+x^3+x^2+x+1) *(1+x+x^2)^2 *(1+x)^3 *(x-1)^6 ). - R. J. Mathar, Dec 15 2011
EXAMPLE
Some solutions for n=7
..6...-7...-5...-5....2....6....2...-1...-1....0...-6...-4....5....1....1...-6
..0....0....1....2...-1....1...-3...-5...-2...-4...-5...-5....4....0....2...-7
.-3....4....2...-2....6....0...-1...-1....0....1....2...-2...-2...-3...-1...-1
.-3....6....1....3...-1...-3...-1....1....3....1....1....5...-6....1....3....4
.-1....2....3....0...-6...-1....1....4....0...-1....5....4...-4....1....1....6
..1...-5...-2....2....0...-3....2....2....0....3....3....2....3....0...-6....4
CROSSREFS
Row 6 of A202252.
Sequence in context: A167963 A085742 A244502 * A324950 A252925 A107965
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 14 2011
STATUS
approved