A176406 - OEIS

%I #7 Feb 03 2019 22:28:15

%S 7,13,19,23,31,33,37,47,49,53,55,63,67,75,83,85,89,91,93,109,113,117,

%T 119,121,127,131,139,141,143,153,157,159,167,175,181,183,185,199,201,

%U 203,207,211,213,215,217,219,233,235,245,247,251,257,263,265,285,287

%N Odd semiprimes minus 2.

%F a(n) = A046315(n) - 2.

%p isA001358 := proc(n) numtheory[bigomega](n) = 2 ; end proc: for n from 1 to 400 by 2 do if isA001358(n+2) then printf("%d,",n) ; end if; end do: # _R. J. Mathar_, Apr 20 2010

%t Select[Range[9,301,2],PrimeOmega[#]==2&]-2 (* _Harvey P. Dale_, May 11 2018 *)

%Y Cf. A007921.

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, Apr 16 2010

%E Entries checked by _R. J. Mathar_, Apr 20 2010