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 A057185 Numbers n such that (19^n + 1)/20 is a prime. 15
 17, 37, 157, 163, 631, 7351, 26183, 30713, 41201, 77951, 476929 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS P. Bourdelais,A Generalized Repunit Conjecture J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002. H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7. H. Lifchitz, Mersenne and Fermat primes field MATHEMATICA Select[Range[0, 10000], PrimeQ[((19^# + 1) / 20)] &] (* Vincenzo Librandi, Mar 20 2015 *) PROG (PRIME95) PRP=1, 19, 476929, 1, 0, 0, "20" # Paul Bourdelais, Mar 20 2015 CROSSREFS Sequence in context: A060429 A052292 A154301 * A157467 A093343 A153685 Adjacent sequences:  A057182 A057183 A057184 * A057186 A057187 A057188 KEYWORD nonn AUTHOR N. J. A. Sloane, Sep 15 2000 EXTENSIONS 26183 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008 a(8)-a(9) give probable primes discovered by Paul Bourdelais, Mar 15 2010 a(10) gives a probable prime discovered by Paul Bourdelais, Mar 18 2010 a(11) gives a probable prime discovered by Paul Bourdelais, Mar 20 2015 STATUS approved

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Last modified December 14 16:38 EST 2019. Contains 329979 sequences. (Running on oeis4.)