A220346 Beginning with a(1)=2, a(n+1) is the a(n)-th palindromic prime.

2, 3, 5, 11, 313, 3075703, 946287424782649

Offset

1,1

Comments

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.

Links

Table of n, a(n) for n=1..7.

Formula

A220346(n+1) = A002385(A220346(n)).

Mathematica

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 *)

Crossrefs

Cf. A002385.

Sequence in context: A075883 A195815 A327428 * A242995 A127814 A162253

Adjacent sequences: A220343 A220344 A220345 * A220347 A220348 A220349

Keyword

nonn,base,hard

Author

James G. Merickel, Dec 11 2012

Status

approved