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A052863
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A simple grammar.
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0
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0, 0, 2, 6, 18, 65, 295, 1652, 11032, 85353, 749203, 7347384, 79564496, 942541041, 12121319327, 168145213732, 2502276609008, 39761200642225, 671855234838915, 12028625060491336, 227451564319791336
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 831
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FORMULA
| E.g.f.: ln(-1/(-1+x))*exp(x)-ln(-1/(-1+x))
Recurrence: {a(1)=0, a(3)=6, a(2)=2, (-n^3-2*n-3*n^2)*a(n)+(19*n+11*n^2+2*n^3+10)*a(n+1)+(-38*n-12*n^2-n^3-36)*a(n+2)+(41+26*n+4*n^2)*a(n+3)+(-17-5*n)*a(n+4)+2*a(n+5), a(4)=18, a(5)=65}
a(n) = A002104(n)-(n-1)!. - Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 03 2005
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MAPLE
| spec := [S, {B=Set(Z, 1 <= card), C=Cycle(Z), S=Prod(B, C)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
| Sequence in context: A150073 A150074 A108066 * A037128 A150075 A150076
Adjacent sequences: A052860 A052861 A052862 * A052864 A052865 A052866
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KEYWORD
| easy,nonn
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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