The sequence is obtained by an application of an Eratosthenes-like sieve to A160217.
Table of n, a(n) for n=1..29.
Cf. A160215 A160216 A160217 A000040
Sequence in context: A167181 A049835 A117510 * A134442 A094179 A085760
Adjacent sequences: A160224 A160225 A160226 * A160228 A160229 A160230
Vladimir Shevelev, May 04 2009, May 06 2009
Edited by N. J. A. Sloane, May 08 2009