[seqfan] Re: Fwd: Primes in an exponential sequence
Richard Mathar
mathar at strw.leidenuniv.nl
Mon Feb 8 14:19:37 CET 2010
> From: vincenzo.librandi at tin.it <vincenzo.librandi at tin.it>
> Date: Sun, Feb 7, 2010 at 20:31
>
>
> I only ask if the sequence
> a(n)=2^(2*n)+2*n+1
> is prime if and only if
> n=3 and n=118 ?
So a(n) = 2^(x-1)+x at x=2n+1 and these x are in A061422. We got
six odd x in A061422 which leads to known solutions n=0, 1, 3, 118, 942, 25690.
RJM
More information about the SeqFan
mailing list