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Search: id:A052942
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| A052942 |
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A simple regular expression. |
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+0
1
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| 1, 1, 1, 1, 3, 5, 7, 9, 15, 25, 39, 57, 87, 137, 215, 329, 503, 777, 1207, 1865, 2871, 4425, 6839, 10569, 16311, 25161, 38839, 59977, 92599, 142921, 220599, 340553, 525751, 811593, 1252791, 1933897, 2985399, 4608585, 7114167, 10981961
(list; graph; listen)
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OFFSET
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0,5
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LINKS
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INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 933
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FORMULA
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G.f.: -1/(-1+x+2*x^4)
Recurrence: {a(1)=1, a(0)=1, a(2)=1, a(3)=1, 2*a(n)+a(n+3)-a(n+4)}
Sum(1/539*(27+72*_alpha^3+96*_alpha^2+128*_alpha)*_alpha^(-1-n), _alpha=RootOf(-1+_Z+2*_Z^4))
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MAPLE
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spec := [S, {S=Sequence(Union(Z, Prod(Union(Z, Z), Z, Z, Z)))}, unlabeled ]: seq(combstruct[count ](spec, size=n), n=0..20);
seq(add(binomial(n-3*k, k)*2^k, k=0..floor(n/3)), n=0..39); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 03 2007
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CROSSREFS
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Sequence in context: A018388 A100866 A102633 this_sequence A117913 A064411 A084229
Adjacent sequences: A052939 A052940 A052941 this_sequence A052943 A052944 A052945
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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 06 2000
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