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A122500
Semiprimes in A006054.
0
25, 183922, 413269, 2086561, 268550439, 77664004259, 1286498670037058, 835992504648428541, 69918194872608910320341, 157104757807495406675035, 353011186440414668176111, 13139449230370726052061293111
OFFSET
1,1
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 *)
CROSSREFS
Sequence in context: A211600 A068737 A151649 * A347812 A251362 A196520
KEYWORD
nonn
AUTHOR
EXTENSIONS
Edited by N. J. A. Sloane, Serp 17 2006
More terms from Robert G. Wilson v, Sep 18 2006
STATUS
approved