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 A152942 #6 Nov 05 2017 13:19:13 %S A152942 1365,1995,2415,2431,2737,2849,3003,3255,3315,3553,3689,4081,4147, %T A152942 4199,4305,4485,4515,4543,4991,5593,5681,5865,6045,6105,6251,6405, %U A152942 6409,6555,6721,6851,7049,7395,7469,7665,7667,7755,7777,7905,8547,8715,8835,9165 %N A152942 Odd squarefree numbers n such that the cyclotomic polynomial Phi(n,x) has height 4. %C A152942 The height of a polynomial is the maximum of the absolute value of its coefficients. Subsequence of A154430. %H A152942 T. D. Noe, <a href="/A152942/b152942.txt">Table of n, a(n) for n = 1..1000</a> %o A152942 (PARI) is(n)=issquarefree(n) && n%2 && vecmax(abs(Vec(polcyclo(n))))==4 \\ _Charles R Greathouse IV_, Nov 05 2017 %Y A152942 Cf. A152955, A152940, A152941, A152943. %K A152942 nonn %O A152942 1,1 %A A152942 _T. D. Noe_, Dec 16 2008, Jan 09 2009