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.

A233460 Prime(n), where n is such that (sum_{i=1..n} prime(i)^16) / n is an integer.

Original entry on oeis.org

2, 28751, 62639, 4620757, 6478193, 2298168044423, 128195718927553
Offset: 1

Views

Author

Robert Price, Dec 10 2013

Keywords

Comments

a(8) > 128971810356197. - Bruce Garner, Mar 24 2021
a(8) > 7.6*10^16. - Paul W. Dyson, Nov 27 2024

Examples

			a(1) = 2, because 2 is the 1st prime and the sum of the first 1 primes^16 = 65536 when divided by 1 equals 65536 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 = 0; Do[sm = sm + Prime[n]^16; 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)^16); s==0 \\ Charles R Greathouse IV, Nov 30 2013
    
  • PARI
    S=n=0;forprime(p=1,,(S+=p^16)%n++||print1(p",")) \\ M. F. Hasler, Dec 01 2013

Formula

a(n) = prime(A131276(n)).

Extensions

a(6)-a(7) from Bruce Garner, Mar 24 2021