%I #5 Mar 30 2012 17:29:13
%S 19,4,5,3,7,9,15,14,1,60,26,28,6,20,13,74,30,111,45,12,16,11,31,102,
%T 144,72,27,65,33,79,21,77,147,91,47,96,37,2,106,200,46,54,44,75,141,
%U 126,165,178,63,36,51,78,210,170,85,143,183,70,48,83,225,411,142,461,270,124
%N a(1) = 19. For n > 1, a(n) is the least unused number such that every concatenation a(n)a(n-1)...a(2)a(1) is prime.
%C Is this a rearrangement of the natural numbers?
%Y Cf. A089710, A089711, A089560-A089573.
%K base,nonn
%O 1,1
%A _Ray Chandler_, Nov 22 2003
%E Edited by _Charles R Greathouse IV_, Apr 29 2010