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.

A233042 Prime(k), where k is such that (1 + Sum_{j=1..k} prime(j)^9) / k is an integer.

Original entry on oeis.org

2, 3, 7, 13, 29, 37, 43, 421, 487, 3373, 5399, 6637, 7333, 117703, 124679, 130829, 218681, 243263, 374537, 2326021, 9423619, 183040409, 224628653, 255740687, 419532599, 707933033, 932059759, 2088543701, 19690779263, 27538667491, 32425948213, 51958163189, 128193738073, 1064987253349
Offset: 1

Views

Author

Robert Price, Dec 03 2013

Keywords

Comments

a(49) > 1005368767096627. - Bruce Garner, Jun 05 2021

Examples

			a(4) = 13, because 13 is the 6th prime and the sum of the first 6 primes^9+1 = 13004773992 when divided by 6 equals 2167462332 which is an integer.
		

Crossrefs

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

Programs

  • Maple
    A233042:=n->if type((1+add(ithprime(i)^9, i=1..n))/n, integer) then ithprime(n); fi; seq(A233042(n), n=1..100000); # Wesley Ivan Hurt, Dec 06 2013
  • Mathematica
    t = {}; sm = 1; Do[sm = sm + Prime[n]^9; If[Mod[sm, n] == 0, AppendTo[t, Prime[n]]], {n, 100000}]; t (* Derived from A217599 *)
  • PARI
    is(n)=if(!isprime(n),return(0)); my(t=primepi(n),s); forprime(p=2,n,s+=Mod(p,t)^9); s==0 \\ Charles R Greathouse IV, Nov 30 2013