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A109693
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Decimal expansion of sum_n=1^inf 1/sigma(n)^2.
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0
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1, 3, 0, 6, 4, 5, 6, 5, 1, 2, 0
(list; constant; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| product_p sum_k=0^inf 1/sigma(p^k)^2
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EXAMPLE
| 1.3064565120...
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PROG
| (PARI) N=1000000000 prodeuler(p=2, N, sum(k=1, 200/log(p), if(k==1, 1., 1./((p^k-1)/(p-1))^2)))*(1+1/N/log(N))
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CROSSREFS
| Cf. Sigma function A000203.
Sequence in context: A088162 A133170 A062542 * A188858 A199610 A004606
Adjacent sequences: A109690 A109691 A109692 * A109694 A109695 A109696
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KEYWORD
| cons,more,nonn
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AUTHOR
| Frank Adams-Watters (FrankTAW(AT)netscape.net), Aug 07 2005
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