A294816 Number of permutations of [n] avoiding {1342, 2314, 4231}.

1, 1, 2, 6, 21, 75, 267, 951, 3407, 12309, 44867, 164891, 610347, 2273020, 8508804, 31991549, 120734511, 457129176, 1735730619, 6607223257, 25207606841, 96365703918, 369070368271, 1415863217868, 5439991258764, 20930861647331, 80638367290921, 311043531047557, 1201127506963082

Offset

0,3

Links

Table of n, a(n) for n=0..28.

D. Callan, T. Mansour, Enumeration of small Wilf classes avoiding 1324 and two other 4-letter patterns, arXiv:1705.00933 [math.CO] (2017), Table 1 No 180.

Maple

C := (1-sqrt(1-4*x))/2/x ;
(1 -7*x +18*x^2 -22*x^3 +16*x^4 -6*x^5 +x^6 -(x -5*x^2 +8*x^3 -2*x^4 -2*x^5 +x^6)*C)/((1 -2*x)*(1 -x)^2*(1 -5*x +4*x^2 -x^3)) ;
taylor(%, x=0, 40) ;
gfun[seriestolist](%) ;

Crossrefs

Sequence in context: A116823 A289597 A116743 * A263790 A247416 A105872

Adjacent sequences: A294813 A294814 A294815 * A294817 A294818 A294819

Keyword

nonn,easy

Author

R. J. Mathar, Nov 09 2017

Status

approved