A233893 Prime(n), where n is such that (1+sum_{i=1..n} prime(i)^4) / n is an integer.

2, 3, 5, 7, 11, 13, 19, 23, 29, 37, 47, 53, 71, 89, 103, 113, 131, 167, 173, 197, 223, 271, 281, 409, 457, 463, 503, 541, 659, 787, 997, 1069, 1279, 1321, 1511, 2203, 2297, 2381, 2423, 3221, 3331, 3413, 3541, 4093, 4327, 5849, 6473, 8291, 9851, 10429, 11177

Offset

1,1

Comments

a(280) > 1701962315686097. - Bruce Garner, Jun 05 2021

Links

Bruce Garner, Table of n, a(n) for n = 1..279 (terms 1..215 from Robert Price)

OEIS Wiki, Sums of powers of primes divisibility sequences

Example

a(6) = 13, because 13 is the 6th prime and the sum of the first 6 primes^4+1 = 46326 when divided by 6 equals 7721 which is an integer.

Mathematica

t = {}; sm = 1; Do[sm = sm + Prime[n]^4; If[Mod[sm, n] == 0, AppendTo[t, Prime[n]]], {n, 100000}]; t (* Derived from A217599 *)
Module[{nn=1400, t}, t=Accumulate[Prime[Range[nn]]^4]+1; Prime[#]&/@ Transpose[Select[Thread[{Range[nn], t}], IntegerQ[#[[2]]/#[[1]]]&]][[1]]](* Harvey P. Dale, Sep 06 2015 *)

Prog

(PARI) is(n)=if(!isprime(n), return(0)); my(t=primepi(n), s); forprime(p=2, n, s+=Mod(p, t)^4); s==0 \\ Charles R Greathouse IV, Nov 30 2013

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: A371694 A106639 A233462 * A232824 A078334 A108696

Adjacent sequences: A233890 A233891 A233892 * A233894 A233895 A233896

Keyword

nonn

Author

Robert Price, Dec 17 2013

Status

approved