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.

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A097350 Numbers n such that (Sum (2k)^k, k=1..n) - 1 is prime.

Original entry on oeis.org

2, 3, 6, 49
Offset: 1

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Author

Rick L. Shepherd, Aug 07 2004

Keywords

Comments

Some of the larger entries may only correspond to probable primes.
Term 49 corresponds to a certified prime (Primo 2.2.0 beta). Next term is greater than 5400. - Ryan Propper, Aug 23 2005

Examples

			6 is a term as 2^1 + 4^2 + 6^3 + 8^4 + 10^5 + 12^6 - 1 = 3090313, which is prime.

Crossrefs

Cf. A073825 (Sum k^k, k=1..n, is prime), A097349 ((Sum (2k)^k, k=1..n) + 1 is prime).

Programs

  • PARI
    s=-1; for(k=1,830, s=s+(2*k)^k; if(isprime(s), print1(k,",")))
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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