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A251936
Number of length 2+2 0..n arrays with the sum of the maximum minus the median of adjacent triples multiplied by some arrangement of +-1 equal to zero.
1
10, 43, 120, 265, 506, 875, 1408, 2145, 3130, 4411, 6040, 8073, 10570, 13595, 17216, 21505, 26538, 32395, 39160, 46921, 55770, 65803, 77120, 89825, 104026, 119835, 137368, 156745, 178090, 201531, 227200, 255233, 285770, 318955, 354936, 393865
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = (1/6)*n^4 + (7/3)*n^3 + (23/6)*n^2 + (8/3)*n + 1.
Conjectures from Colin Barker, Dec 01 2018: (Start)
G.f.: x*(10 - 7*x + 5*x^2 - 5*x^3 + x^4) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.
(End)
EXAMPLE
Some solutions for n=6:
..0....1....5....4....0....4....1....1....0....5....4....6....0....4....4....5
..6....4....0....6....3....2....6....1....2....3....2....6....1....6....1....4
..1....6....4....3....3....3....6....1....1....3....0....6....6....4....0....5
..0....4....5....4....0....4....4....1....1....5....0....0....0....3....4....5
CROSSREFS
Row 2 of A251935.
Sequence in context: A244802 A336288 A211070 * A187673 A297655 A198695
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 11 2014
STATUS
approved