A228463 Number of arrays of maxima of three adjacent elements of some length 8 0..n array.

27, 183, 736, 2227, 5615, 12453, 25096, 46941, 82699, 138699, 223224, 346879, 522991, 768041, 1102128, 1549465, 2138907, 2904511, 3886128, 5130027, 6689551, 8625805, 11008376, 13916085, 17437771, 21673107, 26733448, 32742711, 39838287

Offset

1,1

Links

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

Formula

Empirical: a(n) = (2/45)*n^6 + (8/15)*n^5 + (115/36)*n^4 + 8*n^3 + (1667/180)*n^2 + (149/30)*n + 1.

Conjectures from Colin Barker, Sep 11 2018: (Start)

G.f.: x*(27 - 6*x + 22*x^2 - 27*x^3 + 22*x^4 - 7*x^5 + x^6) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)

Example

Some solutions for n=4:
..4....4....4....3....1....4....4....4....4....1....4....4....0....1....2....0
..2....4....4....1....0....2....2....2....2....0....4....2....1....1....1....0
..0....4....4....0....2....0....1....3....1....0....2....0....1....1....1....0
..0....3....1....1....3....0....3....3....0....2....2....1....2....0....0....1
..0....3....0....4....3....0....4....3....3....2....2....1....3....0....1....1
..2....3....4....4....3....1....4....3....4....3....2....1....4....4....2....4

Crossrefs

Row 6 of A228461.

Sequence in context: A126495 A224454 A258637 * A000499 A365890 A365884

Adjacent sequences: A228460 A228461 A228462 * A228464 A228465 A228466

Keyword

nonn

Author

R. H. Hardin, Aug 22 2013

Status

approved