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A188051
Numbers k such that 18^k - 17^k is prime, or a strong pseudoprime.
2
3, 13, 71, 14533, 26641, 48179
OFFSET
1,1
COMMENTS
Terms < 10000 found by Mike Oakes.
Term 14533 found by Lelio R Paula in June 2008 corresponding to a probable prime with 18243 digits.
Terms 26641 and 48179 found by Jean-Louis Charton in December 2010 corresponding to probable primes with 33442 and 60478 digits.
a(7) > 10^5. - Robert Price, Nov 30 2012
PROG
(PARI) is(n)=ispseudoprime(18^n-17^n) \\ Charles R Greathouse IV, Jun 06 2017
KEYWORD
nonn,hard
AUTHOR
Jean-Louis Charton, Mar 19 2011
EXTENSIONS
Edited by M. F. Hasler, Sep 21 2013
STATUS
approved