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A125907 Numbers k such that k divides 2^4 + 3^4 + 5^4 + ... + prime(k)^4. 4
1, 2951, 38266951, 3053263643573, 3798632877308897 (list; graph; refs; listen; history; text; internal format)
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
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.
Sequence in context: A096628 A051024 A177087 * A025514 A204393 A178273
KEYWORD
bref,hard,more,nonn
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

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Last modified July 18 13:57 EDT 2024. Contains 374378 sequences. (Running on oeis4.)