1,1

A curiosity perhaps worth mentioning is that the decimal representations of the 1st, 3rd and 4th primes generated in this process from a(5) all share the same initial two and final two digits (leading with 10 and ending with 81).

Table of n, a(n) for n=1..5.

The chains in base ten for the first three terms are 2-->3, 7-->13-->37, and

181-->2521-->186733-->148988197.

Sequence in context: A336249 A120381 A260507 * A042359 A015174 A307582

Adjacent sequences: A173237 A173238 A173239 * A173241 A173242 A173243

base,nonn

James G. Merickel, Feb 13 2010

a(5) added by James G. Merickel, Jul 11 2013

approved