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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A236485 Primes p such that gpf(lpf(m)-1) = gpf(gpf(m)-1), where m = 2^p-1 is Mersenne composite.

Original entry on oeis.org

11, 29, 53
Offset: 1

Views

Author

Thomas Ordowski, Jan 27 2014

Keywords

Comments

Conjecture: finitely many such p and gpf(lpf(m)-1) = gpf(gpf(m)-1) = p.
No more terms found up to p = 1277, 1277 being the first prime for which the complete factorization of 2^p-1 is not currently known (see GIMPS link). - Michel Marcus, Jan 29 2014

Links

Crossrefs

Cf. A003260, A016047, A236128.

Programs

  • PARI
    isok(p) = isprime(p) && (mc = (2^p-1)) && (mcpf = (factor(2^p-1))[, 1]) && (length(mcpf) > 1) && (gpf = vecmax(mcpf)) && (lpf = vecmin(mcpf)) && (vecmax(factor(gpf-1)[, 1]) == vecmax(factor(lpf-1)[, 1])); \\ Michel Marcus, Jan 27 2014
Previous Showing 11-11 of 11 results.

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