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A048581
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Numerators 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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2
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47, 53, 829, 79, 857, 1901, 5273, 97, 1787, 5563, 4519, 4057, 19139, 743, 25681, 229, 3687, 18647, 8329, 3853, 51067, 28069, 20483, 335, 72791, 4379, 85093, 22901, 6557, 52673, 112577, 2501, 127759, 13571, 15989, 38083, 161003, 28319, 35813
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| Sum( k>=0, b(k) ) = Pi was the first BBP formula for Pi (Bayley-Borwein-Plouffe in 1995). Allows one to extract any specified binary digit of Pi.
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LINKS
| B. Gourevitch, L'univers de Pi
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FORMULA
| sum( k>=0, b(k) ) = Pi
a(n)=numerator((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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PROG
| (PARI) a(n)=numerator(1/16^n*(4/(8*n+1)-2/(8*n+4)-1/(8*n+5)-1/(8*n+6)))
(PARI) a(n)=numerator((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
| Cf. A066968.
Sequence in context: A141279 A155139 A106279 * A169716 A045140 A104852
Adjacent sequences: A048578 A048579 A048580 * A048582 A048583 A048584
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KEYWORD
| easy,frac,nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 13 2002
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