This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A085900 #20 Feb 23 2024 07:27:51 %S A085900 14,15,28,30,45,56,60,75,90,98,112,120,135,150,180,196,224,225,240, %T A085900 270,300,360,375,392,405,448,450,480,540,600,675,686,720,750,784,810, %U A085900 896,900,960,1080,1125,1200,1215,1350,1372,1440,1500,1568,1620,1792,1800,1875 %N A085900 Numbers k such that k-th cyclotomic polynomial has exactly 3 negative coefficients. %H A085900 Vincenzo Librandi, <a href="/A085900/b085900.txt">Table of n, a(n) for n = 0..96</a> %t A085900 Select[Range@ 2000, Count[CoefficientList[Cyclotomic[#, x], x], _?(# < 0 &)] == 3 &] (* _Michael De Vlieger_, Oct 26 2017 *) %Y A085900 Cf. A085459, A086780. %K A085900 nonn %O A085900 0,1 %A A085900 Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 16 2003 %E A085900 More terms from _Paolo P. Lava_, Oct 26 2017