A216949 Expansion of g.f. (1-6*x+7*x^2)/(1-7*x+11*x^2-x^3).

1, 1, 3, 11, 45, 197, 895, 4143, 19353, 90793, 426811, 2008307, 9454021, 44513581, 209609143, 987068631, 4648293425, 21889908177, 103085198195, 485455690843, 2286142563933, 10766070546453, 50700381312751, 238762035742207, 1124396126301641, 5295090872259961

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Eric Marberg, Crossings and nestings in colored set partitions, arXiv preprint arXiv:1203.5738 [math.CO], 2012-2013.

Lily Yen, Arc-coloured permutations, PSAC 2013, Paris, France, June 24-28, Proc. DMTCS (2013) 743-754.

Lily Yen, Crossings and Nestings for Arc-Coloured Permutations and Automation, Electronic Journal of Combinatorics, 22(1) (2015), #P1.14.

Index entries for linear recurrences with constant coefficients, signature (7,-11,1).

Mathematica

CoefficientList[Series[(1 - 6 x + 7 x^2)/(1 - 7 x + 11 x^2 - x^3), {x, 0, 30}], x] (* Vincenzo Librandi, Mar 11 2013 *)
LinearRecurrence[{7, -11, 1}, {1, 1, 3}, 30] (* Harvey P. Dale, Aug 18 2024 *)

Crossrefs

Sequence in context: A217887 A151129 A151130 * A074532 A049186 A049160

Adjacent sequences: A216946 A216947 A216948 * A216950 A216951 A216952

Keyword

nonn,easy

Author

N. J. A. Sloane, Sep 22 2012

Status

approved