A089710 a(1) = 3. For n > 1, a(n) is the least unused number such that the concatenation a(n)a(n-1)...a(2)a(1) is prime.
3, 1, 6, 9, 4, 20, 13, 29, 19, 2, 7, 18, 12, 41, 36, 30, 72, 25, 27, 8, 28, 42, 47, 114, 85, 38, 16, 117, 177, 24, 11, 66, 34, 53, 37, 264, 48, 126, 96, 87, 39, 261, 99, 65, 124, 419, 21, 147, 55, 321, 240, 62, 40, 69, 92, 60, 49, 287, 289, 393, 227, 745, 84, 149, 58, 54, 141
Offset: 1
Examples
3, 13, 613, 9613, 49613, 2049613, ... etc. are primes.
Crossrefs
Cf. A089711.
Extensions
More terms from Ray Chandler, Nov 21 2003
Edited by Charles R Greathouse IV, Apr 29 2010
Comments