A122499 Semiprimes in A006053.

4, 9, 14, 155, 2993, 9707, 184183, 331981, 1942071, 1263047761, 140390505643

Offset

1,1

Links

Table of n, a(n) for n=1..11.

Mathematica

SemiprimeQ[n_Integer] := Plus @@ (Last /@ FactorInteger[n]) == 2 a = Table[ SeriesCoefficient[ Series[x/(x^3 - 2*x^2 - x + 1), {x, 0, 50}], n], {n, 0, 50}] f[n_] = If[SemiprimeQ[a[[n]]] == True, a[[n]], {}] Flatten[Table[f[n], {n, 1, Length[a]}]]

Crossrefs

Cf. A006054, A006053.

Sequence in context: A105703 A055453 A247013 * A350419 A143709 A010446

Adjacent sequences: A122496 A122497 A122498 * A122500 A122501 A122502

Keyword

nonn

Author

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

Extensions

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

Status

approved