This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A237052 Numbers n such that (49^n + 1)/50 is prime. 0
 7, 19, 37, 83, 1481, 12527, 20149 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are primes. a(8) > 10^5. LINKS 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 Eric Weisstein's World of Mathematics, Repunit. MATHEMATICA Do[ p=Prime[n]; If[ PrimeQ[ (49^p + 1)/50 ], Print[p] ], {n, 1, 9592} ] PROG (PARI) is(n)=ispseudoprime((49^n+1)/50) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS Cf. A000978 = numbers n such that (2^n + 1)/3 is prime. Cf. A007658, A057171, A057172, A057173, A057175, A001562, A057177, A057178, A057179, A057180, A057181, A057182, A057183, A057184, A057185, A057186, A057187, A057188, A057189, A057190, A057191, A071380, A071381, A071382, A084741, A084742, A065507, A126659, A126856, A185240, A229145, A229524, A230036, A229663, A231604, A231865, A235683, A236167, A236530. Sequence in context: A155358 A155353 A155317 * A155381 A155393 A155314 Adjacent sequences:  A237049 A237050 A237051 * A237053 A237054 A237055 KEYWORD hard,more,nonn AUTHOR Robert Price, Feb 02 2014 EXTENSIONS Typo in description corrected by Ray Chandler, Feb 20 2017 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 19 18:30 EST 2019. Contains 320327 sequences. (Running on oeis4.)