A085900 Numbers k such that k-th cyclotomic polynomial has exactly 3 negative coefficients.

14, 15, 28, 30, 45, 56, 60, 75, 90, 98, 112, 120, 135, 150, 180, 196, 224, 225, 240, 270, 300, 360, 375, 392, 405, 448, 450, 480, 540, 600, 675, 686, 720, 750, 784, 810, 896, 900, 960, 1080, 1125, 1200, 1215, 1350, 1372, 1440, 1500, 1568, 1620, 1792, 1800, 1875

Offset: 0

Author

Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 16 2003

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..96

Crossrefs

Cf. A085459, A086780.

Programs

Mathematica

Select[Range@ 2000, Count[CoefficientList[Cyclotomic[#, x], x], ?(# < 0 &)] == 3 &] (* _Michael De Vlieger, Oct 26 2017 *)

Extensions

More terms from Paolo P. Lava, Oct 26 2017