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 A154430 #9 Nov 05 2017 13:20:52 %S A154430 105,165,195,255,273,285,345,357,385,429,455,555,561,595,609,615,627, %T A154430 645,665,705,715,759,777,795,805,897,935,957,969,987,1001,1005,1015, %U A154430 1023,1045,1065,1085,1095,1105,1131,1155,1185,1221,1235,1239,1245,1265 %N A154430 Odd squarefree numbers n such that the cyclotomic polynomial Phi(n,x) has height > 1. %C A154430 The height of a polynomial is the maximum of the absolute value of its coefficients. Different from A118678, which excludes terms that are a multiple of smaller terms. %H A154430 T. D. Noe, <a href="/A154430/b154430.txt">Table of n, a(n) for n = 1..1000</a> %t A154430 Select[Range[2000], OddQ[#] && SquareFreeQ[#] && Max[ Abs[ CoefficientList[ Cyclotomic[#, x], x]]] > 1&] (* _Jean-François Alcover_, Nov 14 2016 *) %o A154430 (PARI) is(n)=issquarefree(n) && n%2 && vecmax(abs(Vec(polcyclo(n))))>1 \\ _Charles R Greathouse IV_, Nov 05 2017 %Y A154430 Cf. A013590, A117318, A117223, A152940, A152941, A152942, A152943, A152955. %K A154430 nonn %O A154430 1,1 %A A154430 _T. D. Noe_, Jan 09 2009