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A061015
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Numerator of Sum_{i=1..n} 1/p(i)^2, p(i) = i-th prime.
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10
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1, 13, 361, 18589, 2293369, 392915461, 114454369129, 41578647715669, 22089188627685001, 18626778064527922741, 17942190650501641587001, 24603083510737933160021269, 41412850736015889039729489289, 76664929233749755566050236079461
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OFFSET
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1,2
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LINKS
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FORMULA
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a(1) = 1; a(n) = a(n-1)*p(n)^2+(p(1)*...*p(n-1))^2. - Zak Seidov, Sep 28 2002
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MAPLE
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summ := 0: for n from 1 to 100 do if (isprime(n)) then summ := summ + 1/n^2; printf("%d, ", numer(summ)); #printf("%d, ", denom(summ)); end if; od; evalf(summ);
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MATHEMATICA
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Numerator[Accumulate[1/Prime[Range[13]]^2]] (* Jayanta Basu, Jul 14 2013 *)
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PROG
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(Python)
from sympy import prime
from fractions import Fraction
from itertools import accumulate, count, islice
def A061015gen(): yield from map(lambda x: x.numerator, accumulate(Fraction(1, prime(k)**2) for k in count(1)))
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CROSSREFS
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KEYWORD
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easy,nonn,frac
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AUTHOR
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Winston C. Yang (winston(AT)cs.wisc.edu), May 21 2001
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EXTENSIONS
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STATUS
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approved
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