A172181 Odd composites not of the form 6k + 1.

9, 15, 21, 27, 33, 35, 39, 45, 51, 57, 63, 65, 69, 75, 77, 81, 87, 93, 95, 99, 105, 111, 117, 119, 123, 125, 129, 135, 141, 143, 147, 153, 155, 159, 161, 165, 171, 177, 183, 185, 189, 195, 201, 203, 207, 209, 213, 215, 219, 221, 225, 231, 237, 243, 245, 249, 255

Offset: 1

Author

Juri-Stepan Gerasimov, Jan 28 2010

Keywords

• nonn
• easy

Crossrefs

Cf. A005408, A045375, A045410. Odd complement is A091300.

Programs

Mathematica

Union[6Range[42] + 3, Select[6Range[43] - 1, Not[PrimeQ[#]] &]] (* Alonso del Arte, Jun 05 2011 *)

PARI

select(n->(n%6==3 && n>3) || (n%6==5 && !isprime(n)), vector(1000,i,i)) \\ Charles R Greathouse IV, Jun 05 2011

Extensions

Entries checked by R. J. Mathar, May 19 2010