%I
%S 1,2,3,2,5,23,7
%N a(1)=1, a(p)=p if p is a prime. Otherwise, start with n and iterate the map (k > concatenation of proper divisors of k) until we reach a prime q; then a(n) = q. If we never reach a prime, a(n) = 1.
%H N. J. A. Sloane et al., <a href="/A120716/a120716.txt">Notes on the attempt to find a(8)</a>
%e 4 > 2, prime, so a(4) = 2.
%e 6 > 2,3 > 23, prime, so a(6) = 23.
%e 8 > 2.4 > 24 > 2.3.4.6.8.12 > 2346812 > 2.4.13.26.52.45131.90262.180524.586703.1173406 > 2413265245131902621805245867031173406 > ? (see link for the continuation)
%e 9 > 3, prime, so a(9) = 3.
%e 21 > 3,7 > 37, prime, so a(21) = 37.
%Y Cf. A120712, A120713, A037274, A130139A130142. A130139 is a bisection.
%K nonn,base,more,hard
%O 1,2
%A _N. J. A. Sloane_, Jul 19 2007
%E a(8) is currently unknown.
