%I #8 Dec 11 2012 19:39:11
%S 2,3,5,11,313,3075703,946287424782649
%N Beginning with a(1)=2, a(n+1) is the a(n)-th palindromic prime.
%C Assuming that no phenomenally strong sieve or counting algorithm for palindromic primes is discovered, a(8) (which is in the vicinity of 10^35) will be beyond reach for at least several years even with the best computing environment.
%F A220346(n+1) = A002385(A220346(n)).
%t palQ[n_] := Module[{d = IntegerDigits[n]}, d == Reverse[d]]; t = {2}; p = 0; cnt = 0; Table[While[cnt < t[[-1]], While[p = NextPrime[p]; ! palQ[p]]; cnt++]; AppendTo[t, p], {5}]; t (* _T. D. Noe_, Dec 11 2012 *)
%Y Cf. A002385.
%K nonn,base,hard
%O 1,1
%A _James G. Merickel_, Dec 11 2012