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Search: id:A052527
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| A052527 |
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A simple regular expression. |
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+0
1
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| 1, 0, 1, 2, 2, 5, 8, 13, 24, 40, 69, 120, 205, 354, 610, 1049, 1808, 3113, 5360, 9232, 15897, 27376, 47145, 81186, 139810, 240765, 414616, 714005, 1229576, 2117432, 3646397, 6279400, 10813653, 18622018, 32068674, 55224945, 95101984
(list; graph; listen)
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OFFSET
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0,4
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LINKS
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INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 453
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FORMULA
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G.f.: -(-1+x)/(1-x-x^3+x^4-x^2)
Recurrence: {a(1)=0, a(0)=1, a(2)=1, a(3)=2, a(n)-a(n+1)-a(n+2)-a(n+3)+a(n+4)}
Sum(-1/39*(-2-11*_alpha+4*_alpha^2+_alpha^3)*_alpha^(-1-n), _alpha=RootOf(1-_Z-_Z^3+_Z^4-_Z^2))
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MAPLE
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spec := [S, {S=Sequence(Prod(Z, Z, Union(Z, Sequence(Z))))}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
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Sequence in context: A035570 A126291 A056224 this_sequence A042982 A006367 A077902
Adjacent sequences: A052524 A052525 A052526 this_sequence A052528 A052529 A052530
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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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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jun 05 2000
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