login
Odd composites not of the form 6k + 1.
0

%I #16 Sep 26 2015 18:39:19

%S 9,15,21,27,33,35,39,45,51,57,63,65,69,75,77,81,87,93,95,99,105,111,

%T 117,119,123,125,129,135,141,143,147,153,155,159,161,165,171,177,183,

%U 185,189,195,201,203,207,209,213,215,219,221,225,231,237,243,245,249,255

%N Odd composites not of the form 6k + 1.

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

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

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

%K nonn,easy

%O 1,1

%A _Juri-Stepan Gerasimov_, Jan 28 2010

%E Entries checked by _R. J. Mathar_, May 19 2010