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Decimal expansion of the convergent to the sum of (1/8)^p where p ranges over the set of prime numbers.
2

%I #12 Aug 11 2020 09:59:06

%S 0,1,7,6,0,9,1,1,9,5,3,3,5,1,7,9,6,5,3,8,5,2,7,8,4,9,7,3,5,6,6,3,1,3,

%T 4,2,6,2,3,8,1,8,1,8,0,1,0,7,9,4,9,6,9,9,4,0,6,4,8,0,1,2,6,8,4,1,2,8,

%U 7,5,4,9,4,1,2,3,2,1,4,4,4,7,2,5,7,5,7,7,3,6,2,4,6,3,2,1,9,6

%N Decimal expansion of the convergent to the sum of (1/8)^p where p ranges over the set of prime numbers.

%F Equals 7 * Sum_{k>=1} pi(k)/8^(k+1), where pi(k) = A000720(k). - _Amiram Eldar_, Aug 11 2020

%e 0.01760911...

%o (PARI) /* Sum of 1/m^p for primes p */ sumnp(n,m) = { local(s=0,a,j); for(x=1,n, s+=1./m^prime(x); ); a=Vec(Str(s)); for(j=3,n, print1(eval(a[j])",") ) }

%Y Cf. A000720, A132822 (base 7), A132821 (base 9).

%K cons,nonn

%O 0,3

%A _Cino Hilliard_, Nov 17 2007

%E Offset corrected _R. J. Mathar_, Jan 26 2009