cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A092062 Numbers k such that A061015(k) is prime.

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%I A092062 #10 Jun 28 2022 15:27:36
%S A092062 2,10,18,36,90,759
%N A092062 Numbers k such that A061015(k) is prime.
%C A092062 a(6) > 447 for a(6) the numerator has more than 2673 digits.
%C A092062 a(7) > 1850. - _Michael S. Branicky_, Jun 27 2022
%F A092062 Numbers k such that numerator of (Sum_{i=1..k} 1/prime(i)^2) is prime
%e A092062 1/2^2 = 1/4 but 1 is not prime, 1/2^2 + 1/3^2 = 13/36 and 13 is prime so a(1)=2.
%o A092062 (PARI) sm(n)= s=0;for(i=1,n,s=s+1/(prime(i)^2));return(s);
%o A092062 for (i=1,400,if(isprime(numerator(sm(i))),print1(i,",")))
%o A092062 (Python) # uses A061015gen() and imports from A061015
%o A092062 from sympy import isprime
%o A092062 def agen():
%o A092062     yield from (k for k, ak in enumerate(A061015gen(), 1) if isprime(ak))
%o A092062 print(list(islice(agen(), 5))) # _Michael S. Branicky_, Jun 27 2022
%Y A092062 Cf. A061015.
%K A092062 hard,nonn
%O A092062 1,1
%A A092062 Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Feb 20 2004
%E A092062 a(6) from _Alexander Adamchuk_, Sep 16 2010