%I #10 Jan 22 2022 08:47:26
%S 9,1,4,5,3,7,12,11,13,42,26,10,17,16,20,82,29,78,57,27,28,66,45,6,69,
%T 33,236,40,116,237,196,65,133,90,60,72,80,61,126,24,153,68,88,122,43,
%U 156,231,285,125,177,249,106,36,147,23,208,483,138,281,63,108,22,38,75,159
%N a(1) = 9. For n > 1, a(n) is the least unused number such that the decimal concatenation a(n)a(n-1)...a(2)a(1) is prime.
%C Is this a permutation of the positive integers?
%C The sequence is infinite by Dirichlet's theorem; Linnik's theorem gives an effectively computable bound on its members. Using Xylouris's version with L <= 5.2, a(n) = 9^(5.2^(n + O(log n))). - _Charles R Greathouse IV_, Apr 27 2010
%Y Cf. A089710, A089711, A089560-A089573.
%K nonn,base
%O 1,1
%A _Ray Chandler_, Nov 22 2003