OFFSET
1,1
COMMENTS
Semiprimes in A032793.
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..11280
EXAMPLE
21 = 3 * 7 which is semiprime and 21 = 1 mod 5.
39 = 3 * 13 which is semiprime and 39 = 4 mod 5.
MATHEMATICA
Select[Range[500], PrimeOmega[#] == 2 && MemberQ[{1, 2, 4}, Mod[#, 5]] &](* Bajpai *)
Select[Complement[Range[100], 5Range[20] - 2, 5Range[20]], PrimeOmega[#] == 2 &] (* Alonso del Arte, Aug 07 2014 *)
PROG
(PARI)
for(n=1, 10^4, if(n!=Mod(0, 5)&&n!=Mod(3, 5), if(bigomega(n)==2, print1(n, ", ")))) \\ Derek Orr, Aug 07 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
K. D. Bajpai, Aug 07 2014
STATUS
approved