A294767 Number of permutations of [n] avoiding {4213, 1432, 1324}.

1, 1, 2, 6, 21, 74, 249, 797, 2451, 7318, 21380, 61449, 174378, 489827, 1364499, 3774779, 10381722, 28410568, 77414615, 210156558, 568645563, 1534219643, 4128788739, 11085822020, 29704820778, 79449163033, 212145068252, 565621458225, 1506010540935, 4004905219913

Offset

0,3

Links

Table of n, a(n) for n=0..29.

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 122.

Index entries for linear recurrences with constant coefficients, signature (8,-25,40,-36,17,-3).

Maple

-(5*x^5-19*x^4+25*x^3-19*x^2+7*x-1)/((x-1)*(x^2-3*x+1)*(3*x^3-5*x^2+4*x-1))   ;
taylor(%, x=0, 40) ;
gfun[seriestolist](%) ;

Crossrefs

Sequence in context: A294698 A294766 A116752 * A116827 A116780 A116777

Adjacent sequences: A294764 A294765 A294766 * A294768 A294769 A294770

Keyword

nonn,easy

Author

R. J. Mathar, Nov 08 2017

Status

approved