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A294696
Number of permutations of [n] avoiding {1423, 2341, 3124}.
0
1, 1, 2, 6, 21, 73, 243, 785, 2511, 8073, 26312, 87257, 294603, 1011602, 3526519, 12456315, 44495535, 160468964, 583421709, 2135814678, 7865015071, 29109558620, 108213772256, 403835324635, 1512193773211, 5679789173645, 21391713994138, 80767323230065, 305638129059811, 1158989815141334, 4403331448837253
OFFSET
0,3
LINKS
MAPLE
C := (1-sqrt(1-4*x))/2/x ;
p := 1-9*x+35*x^2-77*x^3+107*x^4-97*x^5+55*x^6-17*x^7+x^8 ;
q := (1-x)^5*(1-4*x+5*x^2-3*x^3) ;
taylor(p/q*C, x=0, 40) ;
gfun[seriestolist](%) ;
CROSSREFS
Sequence in context: A294804 A116744 A165521 * A116784 A226431 A116802
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Nov 07 2017
STATUS
approved