A112773 3 together with primes multiplied by 3.

3, 6, 9, 15, 21, 33, 39, 51, 57, 69, 87, 93, 111, 123, 129, 141, 159, 177, 183, 201, 213, 219, 237, 249, 267, 291, 303, 309, 321, 327, 339, 381, 393, 411, 417, 447, 453, 471, 489, 501, 519, 537, 543, 573, 579, 591, 597, 633, 669, 681, 687, 699, 717, 723, 753

Offset: 1

Author

Jonathan Vos Post and Ray Chandler, Oct 15 2005

Keywords

• easy
• nonn

Comments

3 times the noncomposite numbers (see formula). Also column 2 of A272400. - Omar E. Pol, Apr 29 2016

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000

Crossrefs

Essentially the same as A001748.

Cf. A000040, A001747, A008578, A008585, A046315.

Programs

Mathematica

Insert[Table[3Prime[n], {n, 1, 60}], 3, 1] (* Stefan Steinerberger, Mar 30 2006 *)

Formula

a(n) = 3*A008578(n). - Omar E. Pol, Jan 31 2012

Extensions

Edited by N. J. A. Sloane, Apr 28 2008 at the suggestion of Alexander R. Povolotsky