login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A131275 Numbers n such that n divides Sum_{k=1..n} (Prime_k)^15. 2
1, 17, 25, 31, 1495, 5555, 8185, 8647, 106841, 187329, 345377, 1811351, 2179119, 2863775, 6368703, 10250821, 59137893, 337430815, 11349203711, 183233304195, 12538656829431 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(21) > 10^12. - Karl-Heinz Hofmann, Apr 12 2021

a(22) > 1.3*10^13. - Bruce Garner, Apr 30 2021

LINKS

Table of n, a(n) for n=1..21.

OEIS Wiki, Sums of powers of primes divisibility sequences.

MATHEMATICA

s = 0; Do[s = s + Prime[n]^15; If[ Mod[s, n] == 0, Print[n]], {n, 400000}]

With[{nn = 3*10^6}, Select[Thread[{Accumulate[Prime[ Range[nn]]^15], Range[ nn]}], Divisible[#[[1]], #[[2]]] &]][[All, 2]] (* This will generate the first 14 terms of the sequence; to generate more, increase the value of nn, but it may take a long time to run. *) (* Harvey P. Dale, Oct 03 2016 *)

CROSSREFS

Cf. A085450 = smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n.

Cf. A007504, A045345, A171399, A128165, A233523, A050247, A050248.

Cf. A024450, A111441, A217599, A128166, A233862, A217600, A217601.

Sequence in context: A336007 A082130 A140609 * A227238 A294689 A263540

Adjacent sequences:  A131272 A131273 A131274 * A131276 A131277 A131278

KEYWORD

more,nonn,less,changed

AUTHOR

Alexander Adamchuk, Jun 25 2007

EXTENSIONS

a(12)-a(17) from Robert G. Wilson v, Jul 02 2007

a(18)-a(19) from Robert Price, Dec 09 2013

a(20) from Karl-Heinz Hofmann, Feb 17 2021

a(21) from Bruce Garner, Apr 30 2021

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 13 03:13 EDT 2021. Contains 343836 sequences. (Running on oeis4.)