cp's OEIS Frontend

A061015 Numerator of Sum_{i=1..n} 1/p(i)^2, p(i) = i-th prime.

%I A061015 #16 Jun 26 2022 11:39:20
%S A061015 1,13,361,18589,2293369,392915461,114454369129,41578647715669,
%T A061015 22089188627685001,18626778064527922741,17942190650501641587001,
%U A061015 24603083510737933160021269,41412850736015889039729489289,76664929233749755566050236079461
%N A061015 Numerator of Sum_{i=1..n} 1/p(i)^2, p(i) = i-th prime.
%H A061015 Michael S. Branicky, <a href="/A061015/b061015.txt">Table of n, a(n) for n = 1..195</a>
%F A061015 a(1) = 1; a(n) = a(n-1)*p(n)^2+(p(1)*...*p(n-1))^2. - _Zak Seidov_, Sep 28 2002
%p A061015 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);
%t A061015 Numerator[Accumulate[1/Prime[Range[13]]^2]] (* _Jayanta Basu_, Jul 14 2013 *)
%o A061015 (Python)
%o A061015 from sympy import prime
%o A061015 from fractions import Fraction
%o A061015 from itertools import accumulate, count, islice
%o A061015 def A061015gen(): yield from map(lambda x: x.numerator, accumulate(Fraction(1, prime(k)**2) for k in count(1)))
%o A061015 print(list(islice(A061015gen(), 20))) # _Michael S. Branicky_, Jun 26 2022
%Y A061015 Cf. A000040, A075986, A075987.
%K A061015 easy,nonn,frac
%O A061015 1,2
%A A061015 Winston C. Yang (winston(AT)cs.wisc.edu), May 21 2001
%E A061015 a(14) and beyond from _Michael S. Branicky_, Jun 26 2022