A294763 Number of permutations of [n] avoiding {4231, 1324, 1234}.

1, 1, 2, 6, 21, 73, 238, 714, 1962, 4957, 11604, 25390, 52361, 102533, 191868, 344970, 598682, 1006793, 1646094, 2624054, 4088421, 6239089, 9342610, 13749770, 19916690, 28429957, 40036336, 55677662, 76531561, 104058701, 140057328, 186725898, 246734674, 323307217, 420312762

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

D. Callan, T. Mansour, Enumeration of small Wilf classes avoiding 1324 and two other 4-letter patterns, arXiv:1705.00933 [math.CO] (2017), Table 2 No 73.

Formula

a(n) = 10*a(n-1) - 45*a(n-2) + 120*a(n-3) - 210*a(n-4) + 252*a(n-5) - 210*a(n-6) + 120*a(n-7) - 45*a(n-8) + 10*a(n-9) - a(n-10) for n > 10. - Chai Wah Wu, Oct 22 2018

Maple

-(x^10-15*x^8+55*x^7-111*x^6+149*x^5-141*x^4+89*x^3-37*x^2+9*x-1)/(x-1)^10   ;
taylor(%, x=0, 40) ;
gfun[seriestolist](%) ;

Mathematica

CoefficientList[Series[-(x^10 - 15 x^8 + 55 x^7 - 111 x^6 + 149 x^5 - 141 x^4 + 89 x^3 - 37 x^2 + 9 x - 1) / (x - 1)^10, {x, 0, 40}], x] (* Vincenzo Librandi, Oct 23 2018 *)

Crossrefs

Sequence in context: A116753 A294762 A294797 * A294798 A294799 A294693

Adjacent sequences: A294760 A294761 A294762 * A294764 A294765 A294766

Keyword

nonn,easy

Author

R. J. Mathar, Nov 08 2017

Status

approved