A250363 Number of length 5 arrays x(i), i=1..5 with x(i) in i..i+n and no value appearing more than 3 times.

32, 243, 1016, 3094, 7712, 16700, 32608, 58826, 99704, 160672, 248360, 370718, 537136, 758564, 1047632, 1418770, 1888328, 2474696, 3198424, 4082342, 5151680, 6434188, 7960256, 9763034, 11878552, 14345840, 17207048, 20507566, 24296144

Offset

1,1

Links

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

Formula

Empirical: a(n) = n^5 + 5*n^4 + 10*n^3 + 5*n^2 + 17*n + 2 for n>2.

Conjectures from Colin Barker, Nov 13 2018: (Start)

G.f.: x*(32 + 51*x + 38*x^2 + 3*x^3 + 8*x^4 - 29*x^5 + 22*x^6 - 5*x^7) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>8.

(End)

Example

Some solutions for n=6:
..1....2....1....2....5....3....5....4....4....3....3....6....2....2....1....3
..3....2....7....4....6....5....5....3....1....1....5....2....7....5....1....7
..6....2....6....5....8....2....4....3....5....7....6....5....8....6....3....4
..4....3....4....8....8....5....6....9....7....4....6....8....4....5....9....9
..4....7....9....4...10...10...10....9....4...10....4...10....9....4...10...10

Crossrefs

Row 5 of A250361.

Sequence in context: A186774 A223952 A224136 * A346637 A017674 A184979

Adjacent sequences: A250360 A250361 A250362 * A250364 A250365 A250366

Keyword

nonn

Author

R. H. Hardin, Nov 19 2014

Status

approved