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 A063699 #9 Apr 30 2019 08:24:50 %S A063699 0,1,0,0,0,0,10,0,0,0,1010,0,100,0,101010,10010010,0,0,1000,0,1000100, %T A063699 100100010010,1010101010,0,10000,0,101010101010,0,10001000100,0, %U A063699 111000,0,0,10010010010010010010,1010101010101010,100001010010100101000010 %N A063699 Positions of negative coefficients in cyclotomic polynomial Phi_n(x), A063698 in binary. %H A063699 <a href="/index/Cy#CyclotomicPolynomialsCoefficients">Index entries for cyclotomic polynomials, positions of coefficients</a> %e A063699 E.g. Phi_15(x) = x^8 - x^7 + x^5 - x^4 + x^3 - x + 1, thus the 1-bits of a(15) are at positions 1,4 and 7, thus we get a(15) = 10010010 %p A063699 map(convert, A063698,binary); %Y A063699 Cf. A063697, A063671, A063672. %K A063699 nonn,base %O A063699 0,7 %A A063699 _Antti Karttunen_, Aug 03 2001