A189323 Number of nondecreasing arrangements of n+2 numbers in 0..6 with the last equal to 6 and each after the second equal to the sum of one or two of the preceding four.

10, 18, 36, 64, 110, 179, 275, 393, 528, 676, 836, 1008, 1192, 1388, 1596, 1816, 2048, 2292, 2548, 2816, 3096, 3388, 3692, 4008, 4336, 4676, 5028, 5392, 5768, 6156, 6556, 6968, 7392, 7828, 8276, 8736, 9208, 9692, 10188, 10696, 11216, 11748, 12292, 12848

Offset

1,1

Comments

Column 6 of A189326.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 6*n^2 + 34*n - 264 for n>8.

Empirical g.f.: x*(10 - 12*x + 12*x^2 + 8*x^4 + 5*x^5 + 4*x^6 - 5*x^7 - 5*x^8 - 4*x^9 - x^10) / (1 - x)^3. - Colin Barker, May 02 2018

Example

Some solutions for n=3:
..1....1....2....2....1....3....1....2....2....0....1....1....3....2....1....1
..5....6....3....4....4....6....5....2....4....3....3....3....3....3....5....3
..5....6....3....4....5....6....5....4....4....3....4....3....3....3....6....3
..5....6....6....4....5....6....6....6....6....3....5....4....6....3....6....6
..6....6....6....6....6....6....6....6....6....6....6....6....6....6....6....6

Crossrefs

Cf. A189326.

Sequence in context: A090995 A363769 A153360 * A064485 A007938 A007937

Adjacent sequences: A189320 A189321 A189322 * A189324 A189325 A189326

Keyword

nonn

Author

R. H. Hardin, Apr 20 2011

Status

approved