The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A216666 Smallest integer b such that (b+1)^p - b^p is prime for all primes p <= prime(n). 1
 1, 1, 1, 1, 6524, 809652228, 30717523794, 55779743835 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS a(1)=a(2)=a(3)=a(4)=1 since 2^2-1, 2^3-1, 2^5-1 and 2^7-1 are primes. Open question: is this sequence infinite? LINKS CROSSREFS Cf. A216668. Sequence in context: A156418 A258521 A068270 * A260979 A034627 A223217 Adjacent sequences:  A216663 A216664 A216665 * A216667 A216668 A216669 KEYWORD nonn,hard,more AUTHOR Jean-Louis Charton, Sep 13 2012 EXTENSIONS a(7)=30717523794, Jean-Louis Charton, Sep 18 1012 a(8)=55779743835, Jean-Louis Charton, Oct 02 1012 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 January 18 16:27 EST 2020. Contains 331011 sequences. (Running on oeis4.)