%I #8 Sep 24 2019 02:37:36
%S 15,26,39,158,326,566,789,961,1159,1262,1369,1478,1591,1718,1849,2582,
%T 3085,3829,4659,5587,7697,8891,10189,13885,14695,16838,17281,18187,
%U 19111,20057,22546,24131,25798,26938,27515,28102,35566,36886,38919,41739,43199,50885
%N Semiprimes that are the sum of the first n odd primes for some n.
%C The set of semiprimes in A071148.
%C Intersection of A001358 and A071148.
%H Robert Israel, <a href="/A274182/b274182.txt">Table of n, a(n) for n = 1..10000</a>
%e 26 appears in the sequence because 26 = 2*13 that is semiprime. Also, 3+5+7+11 = 26.
%e 158 appears in the sequence because 158 = 2*79 that is semiprime. Also, 3+5+7+11+13+17+19+23+29+31 = 158.
%p P:= select(isprime,[seq(i,i=3..10^4,2)]):
%p select(t -> numtheory:-bigomega(t)=2, ListTools:-PartialSums(P)); # _Robert Israel_, Sep 23 2019
%t Select[a = 0; Table[a = a + Prime[k], {k, 2, 300}], PrimeOmega[#] == 2 &]
%o (PARI) s = 0; forprime(p=3, 1e4, s + = p; if (bigomega(s)==2, print1(s, ", ")))
%Y Cf. A001358, A071148, A189072, A274120.
%K nonn
%O 1,1
%A _K. D. Bajpai_, Jun 12 2016