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Odd numbers ending in {1,3,7,9} that are not primes.
0

%I #7 Sep 01 2024 14:52:57

%S 1,9,21,27,33,39,49,51,57,63,69,77,81,87,91,93,99,111,117,119,121,123,

%T 129,133,141,143,147,153,159,161,169,171,177,183,187,189,201,203,207,

%U 209,213,217,219,221,231,237,243,247,249,253,259,261,267,273,279,287

%N Odd numbers ending in {1,3,7,9} that are not primes.

%C Essentially the same as A053795. [From _R. J. Mathar_, Sep 02 2008]

%t Select[Range[1,311,2],MemberQ[{1,3,7,9},Mod[#,10]]&&!PrimeQ[#]&] (* _Harvey P. Dale_, Sep 01 2024 *)

%K nonn

%O 0,2

%A _Roger L. Bagula_, Nov 22 2004