

A062574


Numbers n such that 8^n  7^n is prime or a strong pseudoprime.


4



7, 11, 17, 29, 31, 79, 113, 131, 139, 4357, 44029, 76213, 83663, 173687, 336419, 615997
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OFFSET

1,1


COMMENTS

All terms are prime.  Alexander Adamchuk, Apr 27 2008


LINKS

Table of n, a(n) for n=1..16.
Henri & Renaud Lifchitz, PRP Records.


MATHEMATICA

Select[Range[200], PrimeQ[8^#  7^#] &] (* Vladimir Joseph Stephan Orlovsky, Feb 22 2012 *)


PROG

(PARI) is(n)=ispseudoprime(8^n7^n) \\ Charles R Greathouse IV, Sep 04 2013


CROSSREFS

Cf. A000043, A057468, A059801, A059802, A059803 (9^n8^n is prime), A062572A062666.
Cf. A016177 = 8^n  7^n.
Sequence in context: A021014 A021013 A156105 * A063912 A078725 A247478
Adjacent sequences: A062571 A062572 A062573 * A062575 A062576 A062577


KEYWORD

nonn,hard


AUTHOR

Mike Oakes, May 18 2001, May 19 2001


EXTENSIONS

Two more terms 44029 and 76213 found by Ananda Tallur & JeanLouis Charton in 2003.
Three more terms 83663, 173687 and 336419 found by JeanLouis Charton in 2004 and 2008
New term 615997 found by JeanLouis Charton corresponding to a probable prime with 556301 digits. JeanLouis Charton, Sep 02 2009


STATUS

approved



