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Search: id:A066968
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| A066968 |
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Denominators of b(n) = 1/16^n*(4/(8*n+1)-2/(8*n+4)-1/(8*n+5)-1/(8*n+6)). |
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+0
3
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| 15, 6552, 5026560, 15590400, 4561108992, 244729774080, 15293220913152, 6027885936640, 2292288470384640, 143113842220597248, 2278611404728565760, 39351244081172840448, 3515953192213728460800, 2551413037895138672640
(list; graph; listen)
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OFFSET
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0,1
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LINKS
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B. Gourevitch, L'univers de Pi
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FORMULA
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sum( k>=0, b(k) ) = Pi
a(n)=denominator((1/16)^n*sum(i=1,4,((-1)^(ceil(4/(2*i))))*(floor(4/i))/(8*n+i+floor(sqrt(i-1))*(floor(sqrt(i-1))+1)))) [From Alexander R. Povolotsky (pevnev(AT)juno.com), Aug 31 2009]
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PROGRAM
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(PARI) a(n)=denominator(1/16^n*(4/(8*n+1)-2/(8*n+4)-1/(8*n+5)-1/(8*n+6)))
(PARI) a(n)=denominator((1/16)^n*sum(i=1, 4, ((-1)^(ceil(4/(2*i))))*(floor(4/i))/(8*n+i+floor(sqrt(i-1))*(floor(sqrt(i-1))+1)\ ))) [From Alexander R. Povolotsky (pevnev(AT)juno.com), Aug 31 2009]
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CROSSREFS
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Cf. A048581.
Sequence in context: A070907 A079919 A027513 this_sequence A113795 A074488 A059950
Adjacent sequences: A066965 A066966 A066967 this_sequence A066969 A066970 A066971
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KEYWORD
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easy,frac,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 13 2002
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