A092190 - OEIS

%I #18 Jan 06 2019 14:50:27

%S 4,10,58,185,219,254,377,589,843,917,1247,1707,2157,2519,2642,2771,

%T 3755,4227,5078,5633,6433,6638,7053,9031,15469,16109,17414,18763,

%U 19109,21281,22421,23591,26827,28093,35489,35978,36471,37469,38987,41578,42634

%N Semiprimes that are the sum of the first n semiprimes for some n.

%H Zak Seidov, <a href="/A092190/b092190.txt">Table of n, a(n) for n = 1..5000</a>

%F Equals A062198 intersect A001358. - _M. F. Hasler_, Sep 23 2012

%e 10 is a term because the sum of the first two semiprimes 4 and 6 is 10.

%t s = Select[Range@ 40882, PrimeOmega@ # == 2 &]; Select[Accumulate[s[[1 ;; 164]]], PrimeOmega@ # == 2 &] (* _Michael De Vlieger_, Sep 21 2015 *)

%o (PARI) is_A092190(N)={bigomega(N)==2 & is_A062198(N)}  \\ _M. F. Hasler_, Sep 23 2012

%o (PARI) A092190(n,list=0,b=2)={my(s=0,N=0); while(n, until(bigomega(N++)==b,); bigomega(s+=N)==b & n-- & list & print1(s",")); s}  \\ _M. F. Hasler_, Sep 23 2012

%Y Corresponding values of n: A092189.

%K easy,nonn

%O 1,1

%A _Zak Seidov_, Feb 23 2004