This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A057183 Numbers n such that (17^n + 1)/18 is a prime. 16
 7, 17, 23, 47, 967, 6653, 8297, 41221, 113621, 233689, 348259 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Paul 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 PROG (Prime95) PRP=1, 17, 348259, 1, 0, 0, "18" CROSSREFS Sequence in context: A115591 A265810 A026349 * A076293 A227276 A300298 Adjacent sequences:  A057180 A057181 A057182 * A057184 A057185 A057186 KEYWORD nonn AUTHOR N. J. A. Sloane, Sep 15 2000 EXTENSIONS a(8)=41221 corresponds to a probable prime discovered by Paul Bourdelais, Mar 18 2010 a(9)=113621 corresponds to a probable prime discovered by Paul Bourdelais, Sep 21 2011 a(10)=233689 corresponds to a probable prime discovered by Paul Bourdelais, Sep 03 2013 a(11)=348259 corresponds to a probable prime discovered by Paul Bourdelais, May 22 2014 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 December 13 08:08 EST 2019. Contains 329968 sequences. (Running on oeis4.)