Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.
1,1
Not proved, only Fermat and Lucas PRPs. Next term is greater than 12000. Concerning primes of the form n * 10^n + n + 1, only n=42 yields one for all n up to 7700.
Table of n, a(n) for n=1..4.
Sequence in context: A157998 A234823 A234816 * A235071 A235064 A070835
Adjacent sequences: A110282 A110283 A110284 * A110286 A110287 A110288
more,nonn
Jason Earls (zevi_35711(AT)yahoo.com), Sep 07 2005
approved