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.

A233040 Prime(n), where n is such that (1 + Sum_{i=1..n} prime(i)^7) / n is an integer.

Original entry on oeis.org

2, 3, 7, 11, 13, 29, 37, 199, 15679, 18211, 59359, 78203, 84533, 166399, 528299, 639697, 2080651, 2914033, 5687413, 73463179, 112760273, 156196991, 278840981, 503948113, 3706314893, 3786209711, 12626179519, 13551633533, 13844655553, 24074338279, 37937104823
Offset: 1

Views

Author

Robert Price, Dec 03 2013

Keywords

Comments

a(43) > 458158058915101. - Bruce Garner, Apr 07 2021

Examples

			a(4) = 11, because 11 is the 5th prime and the sum of the first 5 primes^7+1 = 20391155 when divided by 5 equals 4078231, which is an integer.
		

Crossrefs

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

Programs

  • Mathematica
    t = {}; sm = 1; Do[sm = sm + Prime[n]^7; 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)^7); s==0 \\ Charles R Greathouse IV, Nov 30 2013