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A215191
Number of arrays of 4 0..n integers with no sum of consecutive elements equal to a disjoint adjacent sum of an equal number of elements.
1
0, 18, 88, 276, 664, 1366, 2512, 4264, 6800, 10330, 15080, 21308, 29288, 39326, 51744, 66896, 85152, 106914, 132600, 162660, 197560, 237798, 283888, 336376, 395824, 462826, 537992, 621964, 715400, 818990, 933440, 1059488, 1197888, 1349426
OFFSET
1,2
COMMENTS
Row 4 of A215190.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + 5*a(n-4) - 4*a(n-5) + a(n-6).
Conjectures from Colin Barker, Jul 22 2018: (Start)
G.f.: 2*x^2*(9 + 8*x + 7*x^2) / ((1 - x)^5*(1 + x)).
a(n) = n*(3*n^3 + n^2 - 1)/3 for n even.
a(n) = (3*n^4 + n^3 - n - 3)/3 for n odd.
(End)
EXAMPLE
Some solutions for n=6:
2 4 6 0 0 6 6 2 0 0 1 6 5 4 3 3
4 3 0 4 5 0 1 3 2 4 4 0 6 5 4 5
1 5 4 0 1 6 2 5 5 1 3 4 2 6 0 3
0 1 6 3 3 3 3 1 4 5 0 3 0 0 3 4
CROSSREFS
Cf. A215190.
Sequence in context: A126405 A250101 A141842 * A063788 A066854 A247901
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 05 2012
STATUS
approved