A122500 Semiprimes in A006054.

25, 183922, 413269, 2086561, 268550439, 77664004259, 1286498670037058, 835992504648428541, 69918194872608910320341, 157104757807495406675035, 353011186440414668176111, 13139449230370726052061293111

Offset: 1

Author

Roger L. Bagula and Gary W. Adamson, Sep 15 2006

Keywords

• nonn

Crossrefs

Cf. A006054, A006053.

Programs

Mathematica

semiPrimeQ[n_Integer] := Plus @@ Last /@ FactorInteger[n] == 2; s = CoefficientList[ Series[x/(x^3 - x^2 - 2*x + 1), {x, 0, 100}], x]; Select[s, SemiprimeQ@# &]
Select[LinearRecurrence[{2,1,-1},{0,0,1},100],PrimeOmega[#]==2&] (* Harvey P. Dale, Aug 21 2013 *)

Extensions

Edited by N. J. A. Sloane, Sep 17 2006

More terms from Robert G. Wilson v, Sep 18 2006