A085711 - OEIS

%I #12 Dec 14 2019 08:09:17

%S 4,8,9,14,20,21,24,25,26,27,30,32,33,36,38,44,46,49,57,62,68,69,70,74,

%T 84,85,93,94,100,102,105,106,112,116,120,121,124,125,126,128,129,133,

%U 134,135,144,145,150,152,160,162,166,169,171,174,177,178,180,182,188

%N Numbers k such that sopfr(k) is a semiprime.

%H Amiram Eldar, <a href="/A085711/b085711.txt">Table of n, a(n) for n = 1..10000</a>

%e 19770 = 2*3*5*659 is a term because 2+3+5+659 = 669 = 3*223.

%t seqQ[n_] := PrimeOmega[Plus @@ Times @@@ FactorInteger[n]] == 2; Select[Range[200], seqQ] (* _Amiram Eldar_, Dec 14 2019 *)

%Y Cf. A001358, A001414.

%K easy,nonn

%O 1,1

%A _Jason Earls_, Jul 19 2003