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A085900
Numbers k such that k-th cyclotomic polynomial has exactly 3 negative coefficients.
1
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
0,1
LINKS
MATHEMATICA
Select[Range@ 2000, Count[CoefficientList[Cyclotomic[#, x], x], _?(# < 0 &)] == 3 &] (* Michael De Vlieger, Oct 26 2017 *)
CROSSREFS
Sequence in context: A084429 A207036 A087430 * A075659 A022104 A041398
KEYWORD
nonn
AUTHOR
Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 16 2003
EXTENSIONS
More terms from Paolo P. Lava, Oct 26 2017
STATUS
approved