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

1,1

Links

Dana Jacobsen, Table of n, a(n) for n = 1..340

Mathematica

Select[Prime[Range[13000]], Times@@FactorInteger[#^2-1][[All, 1]]<#&] (* Harvey P. Dale, Apr 10 2017 *)

Prog

(Perl) use ntheory ":all"; forprimes { say if vecprod(map { $_->[0] } factor_exp($_**2-1)) < $_ } 1e6; # Dana Jacobsen, Aug 09 2016

Crossrefs

Cf. A007947, A275630.

Sequence in context: A045425 A364189 A099983 * A048860 A233930 A292447

Adjacent sequences: A275628 A275629 A275630 * A275632 A275633 A275634

Keyword

nonn

Author

N. J. A. Sloane, Aug 07 2016, following a suggestion from J. M. Bergot.

Extensions

Terms a(10) and beyond from Dana Jacobsen, Aug 09 2016

Status

approved