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A224470
Numbers n such that 7^n - n is prime.
3
2, 6, 8, 12, 44, 48, 512, 1088, 1104, 6038
OFFSET
1,1
COMMENTS
a(11) > 92000. - Giovanni Resta, Apr 08 2013
a(11) > 2*10^5. - Robert Price, Feb 11 2014
PROG
(PARI) forstep(n=2, 10^4, 2, if(ispseudoprime(7^n-n), print1(n, ", "))); /* Joerg Arndt, Apr 07 2013 */
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Alex Ratushnyak, Apr 06 2013
STATUS
approved