A256428 G.f.: x^2*(1-2*x)/(1-8*x+22*x^2-26*x^3+14*x^4-5*x^5+x^6).

0, 0, 1, 6, 26, 102, 386, 1441, 5353, 19854, 73612, 272940, 1012137, 3753696, 13922343, 51640040, 191546040, 710504359, 2635506573, 9776051185, 36263011505, 134513166002, 498960289449, 1850833274594, 6865444733208, 25466548032582

Offset

0,4

Links

Table of n, a(n) for n=0..25.

Miklós Bóna, A new record for 1324-avoiding permutations, arXiv:1404.4033 [math.CO], 2014.

Miklós Bóna, A new record for 1324-avoiding permutations, European Journal of Mathematics (2015) 1:198-206, DOI 10.1007/s40879-014-0020-6.

Mathematica

CoefficientList[Series[x^2 (1 - 2 x)/(1 - 8 x + 22 x^2 - 26 x^3 + 14 x^4 - 5 x^5 + x^6), {x, 0, 25}], x] (* Michael De Vlieger, Aug 27 2015 *)

Prog

(PARI) concat([0, 0], Vec(x^2*(1-2*x)/(1-8*x+22*x^2-26*x^3+14*x^4-5*x^5+x^6) + O(x^40))) \\ Michel Marcus, Aug 27 2015

Crossrefs

Sequence in context: A034560 A307306 A143955 * A196860 A254317 A037545

Adjacent sequences: A256425 A256426 A256427 * A256429 A256430 A256431

Keyword

nonn

Author

N. J. A. Sloane, Apr 13 2015

Status

approved