A275631 Primes p such that the product of the distinct prime factors of p^2-1 is less than p.
3, 7, 17, 31, 97, 127, 251, 449, 487, 577, 1151, 1249, 1567, 1999, 2663, 4801, 4999, 7937, 8191, 12799, 13121, 13183, 15551, 31249, 31751, 32257, 33857, 35153, 39367, 65537, 79201, 81919, 85751, 115249, 117127, 124001, 126001, 131071
Offset: 1
Keywords
Links
- Dana Jacobsen, Table of n, a(n) for n = 1..340
Programs
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Mathematica
Select[Prime[Range[13000]],Times@@FactorInteger[#^2-1][[All,1]]<#&] (* Harvey P. Dale, Apr 10 2017 *)
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Perl
use ntheory ":all"; forprimes { say if vecprod(map { $->[0] } factor_exp($**2-1)) < $ } 1e6; # _Dana Jacobsen, Aug 09 2016
Extensions
Terms a(10) and beyond from Dana Jacobsen, Aug 09 2016