A046422 Numbers requiring 2 steps to reach a prime under the prime factor concatenation procedure.

4, 9, 24, 30, 32, 36, 38, 42, 50, 55, 57, 60, 68, 74, 75, 88, 92, 94, 99, 102, 106, 108, 110, 122, 134, 140, 155, 158, 174, 194, 206, 209, 215, 231, 244, 254, 272, 280, 287, 298, 299, 306, 314, 323, 332, 334, 346, 351, 362, 365, 371, 374, 398, 413, 415, 417

Offset: 1

Author

Patrick De Geest, Jun 15 1998

Keywords

• nonn
• base

Examples

			24 = 2*2*2*3, 2223 = 3*3*13*19, 331319 is prime.
		

Links

• P. De Geest, Home Primes

Crossrefs

Cf. A037271, A046411.

Extensions

Edited by Charles R Greathouse IV, Apr 28 2010