A089564 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.

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, 33, 236, 40, 116, 237, 196, 65, 133, 90, 60, 72, 80, 61, 126, 24, 153, 68, 88, 122, 43, 156, 231, 285, 125, 177, 249, 106, 36, 147, 23, 208, 483, 138, 281, 63, 108, 22, 38, 75, 159

Offset: 1

Author

Ray Chandler, Nov 22 2003

Keywords

• nonn
• base

Comments

Is this a permutation of the positive integers?

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

Crossrefs

Cf. A089710, A089711, A089560-A089573.