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A174267 Primes p such that 5^p-4 is also prime. 0
5, 7, 47 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..3.

FORMULA

A000040 INTERSECT A059613. - R. J. Mathar, Apr 15 2010

EXAMPLE

For p=5, 5^5-4=3121; p=7, 5^7-4=78121; p=47, 5^47-4= 710542735760100185871124267578121

PROG

(MAGMA) [ p: p in PrimesUpTo(3500)| IsPrime(5^p-4)]

(PARI) is(n)=isprime(n) && isprime(5^n-4) \\ Charles R Greathouse IV, Sep 06 2016

CROSSREFS

Sequence in context: A090520 A066219 A278618 * A306649 A075830 A058313

Adjacent sequences:  A174264 A174265 A174266 * A174268 A174269 A174270

KEYWORD

nonn,more,bref

AUTHOR

Vincenzo Librandi, Mar 14 2010

STATUS

approved

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Last modified June 19 16:48 EDT 2019. Contains 324222 sequences. (Running on oeis4.)