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Search: id:A052837
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| 0, 0, 1, 4, 10, 22, 43, 80, 141, 240, 397, 640, 1011, 1568, 2395, 3604, 5360, 7876, 11460, 16510, 23588, 33418, 47006, 65640, 91085, 125596, 172215, 234820, 318579, 430060, 577920, 773130, 1030007, 1366644, 1806445, 2378892, 3121835, 4082796
(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 804
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FORMULA
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G.f.: (exp(Sum(-x^j[1]/(x^j[1]-1)/j[1], j[1]=1 .. infinity))-1)^2
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MAPLE
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spec := [S, {C=Sequence(Z, 1 <= card), B=Set(C, 1 <= card), S=Prod(B, B)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
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Essentially the same as A048574.
Sequence in context: A034357 A023626 A048574 this_sequence A052821 A023628 A004798
Adjacent sequences: A052834 A052835 A052836 this_sequence A052838 A052839 A052840
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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 Frank Adams-Watters (FrankTAW(AT)Netscape.net), Feb 08 2006
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