A183908 Number of nondecreasing arrangements of n+2 numbers in 0..5 with each number being the sum mod 6 of two others.

2, 8, 37, 124, 309, 637, 1163, 1953, 3085, 4650, 6753, 9514, 13069, 17571, 23191, 30119, 38565, 48760, 60957, 75432, 92485, 112441, 135651, 162493, 193373, 228726, 269017, 314742, 366429, 424639, 489967, 563043, 644533, 735140, 835605, 946708

Offset

1,1

Comments

Column 5 of A183912.

Links

R. H. Hardin, Table of n, a(n) for n = 1..132

Formula

Empirical: a(n) = (1/120)*n^5 + (5/24)*n^4 + (49/24)*n^3 - (29/24)*n^2 - (461/20)*n + 43 for n>2.

Conjectures from Colin Barker, Apr 06 2018: (Start)

G.f.: x*(2 - 4*x + 19*x^2 - 18*x^3 - 10*x^4 + 11*x^5 + 5*x^6 - 4*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>7.

(End)

Example

All solutions for n=2:
..0....0....0....2....0....1....1....0
..2....0....0....2....2....2....3....3
..2....3....0....4....4....3....4....3
..4....3....0....4....4....5....5....3

Crossrefs

Cf. A183912.

Sequence in context: A052618 A055142 A340234 * A280119 A224032 A046814

Adjacent sequences: A183905 A183906 A183907 * A183909 A183910 A183911

Keyword

nonn

Author

R. H. Hardin, Jan 07 2011

Status

approved