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 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are prime. - Alexander Adamchuk, Apr 27 2008 LINKS 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^n-7^n) \\ Charles R Greathouse IV, Sep 04 2013 CROSSREFS Cf. A000043, A057468, A059801, A059802, A059803 (9^n-8^n is prime), A062572-A062666. 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 & Jean-Louis Charton in 2003. Three more terms 83663, 173687 and 336419 found by Jean-Louis Charton in 2004 and 2008 New term 615997 found by Jean-Louis Charton corresponding to a probable prime with 556301 digits. Jean-Louis Charton, Sep 02 2009 STATUS approved

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Last modified April 2 19:05 EDT 2020. Contains 333190 sequences. (Running on oeis4.)