

A163489


Indices n such that composite(n)/3 is prime.


0



2, 4, 8, 12, 21, 26, 35, 40, 49, 63, 68, 81, 92, 97, 106, 121, 136, 140, 154, 165, 171, 185, 195, 210, 229, 240, 245, 254, 260, 270, 305, 315, 330, 336, 360, 365, 379, 395, 405, 421, 437, 442, 467, 472, 483, 488, 517, 547, 557, 562, 573, 589, 594, 619, 634, 650
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


LINKS

Table of n, a(n) for n=1..56.


EXAMPLE

a(1)=2 (2nd composite/3 = 6/3 = 2, which is prime).
a(2)=4 (4th composite/3 = 9/3 = 3, which is prime).


CROSSREFS

Cf. A000040, A002808.
Sequence in context: A322419 A246850 A294066 * A095352 A076651 A081410
Adjacent sequences: A163486 A163487 A163488 * A163490 A163491 A163492


KEYWORD

nonn,easy


AUTHOR

JuriStepan Gerasimov, Jul 29 2009


EXTENSIONS

48 replaced by 49, 62 replaced by 63, 96 by 97, etc.  R. J. Mathar, Oct 09 2009


STATUS

approved



