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.

A233350 Prime(k), where k is such that (1 + Sum_{i=1..k} prime(i)^13) / k is an integer.

Original entry on oeis.org

2, 3, 7, 13, 29, 37, 239, 373, 769, 1531, 2011, 5003, 11939, 14557, 14629, 37361, 204361, 252431, 289193, 1403189, 2201623, 2299541, 6287173, 6734179, 29155393, 29235133, 103558313, 186122161, 531627839, 623579347, 4245274987, 6718076401, 16495027789, 39151049879, 90009559583, 225919038109
Offset: 1

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Author

Robert Price, Dec 07 2013

Keywords

Comments

a(47) > 458158058915101. - Bruce Garner, May 05 2021

Examples

			a(4) = 13, because 13 is the 6th prime and the sum of the first 6 primes^13+1 = 337495930052232 when divided by 6 equals 56249321675372 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]^13; 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)^13); s==0 \\ Charles R Greathouse IV, Nov 30 2013