Search: id:A052663 Results 1-1 of 1 results found. %I A052663 %S A052663 0,0,0,0,24,240,720,5040,40320,362880,3628800,39916800,479001600, %T A052663 6227020800,87178291200,1307674368000,20922789888000,355687428096000, %U A052663 6402373705728000,121645100408832000,2432902008176640000 %N A052663 A simple regular expression in a labeled universe. %H A052663 INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 610 %F A052663 E.g.f.: x^4*(-x+x^2-1)/(-1+x) %F A052663 Recurrence: {a(1)=0, a(0)=0, a(2)=0, (-1-n)*a(n)+a(n+1), a(3)=0, a(4)=24, a(6)=720, a(5)=240} %F A052663 n! for n >= 4. %p A052663 spec := [S,{S=Prod(Z,Z,Z,Z,Union(Z,Sequence(Z)))},labeled]: seq(combstruct[count](spec, size=n), n=0..20); %Y A052663 Sequence in context: A003272 A003245 A006863 this_sequence A167548 A052796 A056269 %Y A052663 Adjacent sequences: A052660 A052661 A052662 this_sequence A052664 A052665 A052666 %K A052663 easy,nonn %O A052663 0,5 %A A052663 encyclopedia(AT)pommard.inria.fr, Jan 25 2000 Search completed in 0.001 seconds