A209321 Indices n for which A209312(n)=2.

9, 11, 14, 17, 26, 31, 38, 46, 62, 70, 74, 86, 94, 118, 134, 194, 206, 278, 286, 566, 598, 778, 842, 934, 1006, 1082, 1214, 1238, 1546, 1574, 1726, 1858, 2018, 2278, 2474, 2774, 3142, 3686

Offset

1,1

Comments

Many of these seem to be even semiprimes.

Is this sequence infinite, and if so, can someone exhibit an explicitely calculable subsequence?

Links

Table of n, a(n) for n=1..38.

Crossrefs

Sequence in context: A341080 A279519 A307188 * A212816 A183980 A101754

Adjacent sequences: A209318 A209319 A209320 * A209322 A209323 A209324

Keyword

nonn,more

Author

M. F. Hasler, Jan 19 2013

Status

approved