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Search: id:A052592
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| A052592 |
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A simple regular expression in a labeled universe. |
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+0
1
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| 1, 3, 24, 288, 4608, 92160, 2211840, 61931520, 1981808640, 71345111040, 2853804441600, 125567395430400, 6027234980659200, 313416218994278400, 17551308263679590400, 1053078495820775424000, 67397023732529627136000
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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A simple regular expression in a labeled universe.
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LINKS
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INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 537
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FORMULA
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E.g.f.: (-1+x)/(-1+4*x)
Recurrence: {a(0)=1, a(1)=3, (-4-4*n)*a(n)+a(n+1)}
3*4^(n-1)*n!
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MAPLE
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spec := [S, {S=Sequence(Prod(Sequence(Z), Union(Z, Z, Z)))}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
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Adjacent sequences: A052589 A052590 A052591 this_sequence A052593 A052594 A052595
Sequence in context: A081133 A064037 A128572 this_sequence A059381 A138209 A075142
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KEYWORD
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easy,nonn
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AUTHOR
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encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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