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 A066968 Denominators of b(n) = (1/16)^n*(4/(8*n+1) - 2/(8*n+4) - 1/(8*n+5) - 1/(8*n+6)). 3
 15, 6552, 5026560, 15590400, 4561108992, 244729774080, 15293220913152, 6027885936640, 2292288470384640, 143113842220597248, 2278611404728565760, 39351244081172840448, 3515953192213728460800, 2551413037895138672640 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS G. C. Greubel, Table of n, a(n) for n = 0..815 B. Gourevitch, L'univers de Pi FORMULA Sum_{k>=0} b(k) = Pi. MATHEMATICA Denominator[Table[1/16^n (4/(8n+1)-2/(8n+4)-1/(8n+5)-1/(8n+6)), {n, 0, 20}]] (* Harvey P. Dale, Jul 16 2014 *) PROG (PARI) a(n)=denominator(1/16^n*(4/(8*n+1)-2/(8*n+4)-1/(8*n+5)-1/(8*n+6))) CROSSREFS Cf. A048581. Sequence in context: A292972 A204677 A198250 * A113795 A205155 A208095 Adjacent sequences:  A066965 A066966 A066967 * A066969 A066970 A066971 KEYWORD easy,frac,nonn AUTHOR Benoit Cloitre, Aug 13 2002 STATUS approved

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Last modified March 30 16:16 EDT 2020. Contains 333127 sequences. (Running on oeis4.)