A092190 Semiprimes that are the sum of the first n semiprimes for some n.

4, 10, 58, 185, 219, 254, 377, 589, 843, 917, 1247, 1707, 2157, 2519, 2642, 2771, 3755, 4227, 5078, 5633, 6433, 6638, 7053, 9031, 15469, 16109, 17414, 18763, 19109, 21281, 22421, 23591, 26827, 28093, 35489, 35978, 36471, 37469, 38987, 41578, 42634

Offset

1,1

Links

Zak Seidov, Table of n, a(n) for n = 1..5000

Formula

Equals A062198 intersect A001358. - M. F. Hasler, Sep 23 2012

Example

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

Mathematica

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

Prog

(PARI) is_A092190(N)={bigomega(N)==2 & is_A062198(N)}  \\ M. F. Hasler, Sep 23 2012
(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

Crossrefs

Corresponding values of n: A092189.

Sequence in context: A348514 A254078 A104363 * A328036 A222675 A328155

Adjacent sequences: A092187 A092188 A092189 * A092191 A092192 A092193

Keyword

easy,nonn

Author

Zak Seidov, Feb 23 2004

Status

approved