A106355 Number of compositions of n into 6 parts such that no two adjacent parts are equal.

2, 10, 30, 76, 168, 320, 580, 968, 1558, 2380, 3540, 5078, 7160, 9804, 13238, 17510, 22884, 29418, 37462, 47054, 58638, 72272, 88454, 107262, 129312, 154644, 183994, 217442, 255782, 299114, 348386, 403652, 466012, 535550, 613442, 699812, 796012, 902102, 1019612

Offset

9,1

Links

Alois P. Heinz, Table of n, a(n) for n = 9..1000

A. Knopfmacher and H. Prodinger, On Carlitz compositions, European Journal of Combinatorics, Vol. 19, 1998, pp. 579-589.

Formula

G.f.: 2 *(16*x^12 +16*x^11 +31*x^10 +40*x^9 +53*x^8 +51*x^7 +51*x^6 +39*x^5 +31*x^4 +18*x^3 +9*x^2 +4*x+1) *x^9 / ((x^2-x+1) *(x^4+x^3+x^2+x+1) *(x^2+1) *(x^2+x+1)^2 *(x+1)^3 *(x-1)^6). - Alois P. Heinz, Sep 04 2015

Crossrefs

Column 6 of A106351. Cf. A003242.

Sequence in context: A034827 A328532 A051667 * A120546 A058966 A058967

Adjacent sequences: A106352 A106353 A106354 * A106356 A106357 A106358

Keyword

nonn,easy

Author

Christian G. Bower, Apr 29 2005

Extensions

Replaced broken link, Vaclav Kotesovec, May 01 2014

Status

approved