OFFSET
1,1
COMMENTS
REFERENCES
Wilfrid Keller, personal communication, 2010.
LINKS
Chris K. Caldwell, The List of Largest Known Primes, 270704167 * 2^85461 - 1
Chris K. Caldwell, The List of Largest Known Primes, 3296757029 * 2^191207 + 1
Carlos Rivera, Problem 30. A stepladder to B-alpha sequence, The Prime Puzzles & Problems Connection.
MATHEMATICA
l = -1; Flatten[Table[p = Prime[n]; k = 0; While[! PrimeQ[p*2^k - 1] && ! PrimeQ[p*2^k + 1], k++]; If[k > l, l = k; p, {}], {n, 10^4}]] (* Arkadiusz Wesolowski, Sep 04 2011 *)
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Arkadiusz Wesolowski, Aug 31 2011
EXTENSIONS
a(17) was found in 2000 by Wilfrid Keller
a(18) was found in 2003 by Patrick De Geest
Edited by Max Alekseyev, Oct 14 2012
Edited by Arkadiusz Wesolowski, Sep 11 2013
STATUS
approved