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 A222265 Numbers n such that (13^n + 2^n)/15 is prime. 2
 7, 31, 103, 223, 503, 1171, 1973, 4111, 4729 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are prime. a(10) > 10^5. LINKS MATHEMATICA Select[Prime[Range[1, 100000]], PrimeQ[(13^# + 2^#)/15]&] PROG (PARI) forprime(p=3, 10^6, if(ispseudoprime((13^p + 2^p)/15), print1(p, ", ") ) ); \\ Joerg Arndt, Jul 29 2013 CROSSREFS Cf. A125956, A125957, A057159, A128071, A213176. Sequence in context: A055899 A218956 A139876 * A107392 A054497 A235593 Adjacent sequences:  A222262 A222263 A222264 * A222266 A222267 A222268 KEYWORD nonn,hard,more AUTHOR Robert Price, May 05 2013 EXTENSIONS Removed incorrect first term of "2". STATUS approved

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Last modified June 19 15:47 EDT 2021. Contains 345142 sequences. (Running on oeis4.)