|
|
A294820
|
|
Number of permutations of [n] avoiding {1324, 2341, 1243}.
|
|
0
|
|
|
1, 1, 2, 6, 21, 76, 275, 989, 3544, 12696, 45578, 164194, 593966, 2158090, 7875503, 28862235, 106203597, 392291117, 1454239837, 5409048372, 20182045236, 75522431214, 283377791271, 1065990318403, 4019415215923, 15188857311110, 57514327098488, 218201177979480, 829305547436095
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
LINKS
|
|
|
MAPLE
|
C := (1-sqrt(1-4*x))/2/x ;
((1 -7*x +19*x^2 -25*x^3 +13*x^4 +4*x^5 -5*x^6 +x^7)*C -1 +7*x -19*x^2 +23*x^3 -7*x^4 -7*x^5 +4*x^6)/(x*(1 -x)^2*(1 -3*x +x^2)*(1 -x -x^2));
taylor(%, x=0, 40) ;
gfun[seriestolist](%) ;
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|