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Search: id:A052943
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| A052943 |
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A simple regular expression. |
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+0
1
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| 1, 0, 1, 1, 2, 2, 5, 5, 11, 13, 25, 32, 58, 78, 135, 189, 316, 455, 743, 1091, 1752, 2609, 4140, 6227, 9798, 14842, 23214, 35342, 55043, 84100, 130586, 200029, 309930, 475601, 735789, 1130546, 1747150, 2686951, 4149245, 6385263, 9854895
(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 934
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FORMULA
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G.f.: -(-1+x^2)/(1-2*x^2-x^3+x^5)
Recurrence: {a(1)=0, a(0)=1, a(2)=1, a(3)=1, a(4)=2, a(n)-a(n+2)-2*a(n+3)+a(n+5)}
Sum(-1/4511*(-330+224*_alpha^2-1089*_alpha+100*_alpha^4+167*_alpha^3)*_alpha^(-1-n), _alpha=RootOf(1-2*_Z^2-_Z^3+_Z^5))
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MAPLE
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spec := [S, {S=Sequence(Prod(Z, Z, Union(Z, Sequence(Prod(Z, Z)))))}, unlabeled ]: seq(combstruct[count ](spec, size=n), n=0..20);
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CROSSREFS
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Sequence in context: A079964 A103891 A005294 this_sequence A032580 A002014 A135153
Adjacent sequences: A052940 A052941 A052942 this_sequence A052944 A052945 A052946
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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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