OFFSET
1,2
COMMENTS
No more terms to 10^13. - Charles R Greathouse IV, Mar 21 2011
a(4) is less than 10^13 contradicting the previous comment. It was found using the primesieve library by Kim Walisch and gmplib. - Bruce Garner, Feb 26 2021
a(6) > 4*10^15. - Paul W. Dyson, Nov 19 2024
LINKS
MATHEMATICA
a(1) = 1; s = 2^4; Do[s = s + Prime[2n]^4+Prime[2n+1]^4; If[ Mod[s, 2n+1] == 0, Print[2n+1]], {n, 1, 20000000}]
PROG
(PARI) s=0; n=0; forprime(p=2, 4e9, s+=p^4; if(s%n++==0, print1(n", "))) \\ Charles R Greathouse IV, Mar 21 2011
CROSSREFS
Cf. A085450 = smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n.
KEYWORD
bref,hard,more,nonn,changed
AUTHOR
Alexander Adamchuk, Feb 04 2007
EXTENSIONS
a(4) from Bruce Garner, Feb 26 2021
a(5) from Paul W. Dyson, May 09 2024
STATUS
approved