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.

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

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Adjacent sequences: A251933 A251934 A251935 * A251937 A251938 A251939

Keyword

nonn

Author

R. H. Hardin, Dec 11 2014

Status

approved