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 A063697 #15 May 08 2023 19:45:13 %S A063697 0,10,11,111,101,11111,101,1111111,10001,1001001,10101,11111111111, %T A063697 10001,1111111111111,1010101,100101001,100000001,11111111111111111, %U A063697 1000001,1111111111111111111,100010001,1001001001001,10101010101 %N A063697 Positions of positive coefficients in cyclotomic polynomial Phi_n(x), A063696 in binary. %H A063697 <a href="/index/Cy#CyclotomicPolynomialsCoefficients">Index entries for cyclotomic polynomials, positions of coefficients</a> %e A063697 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 0,3,5 and 8, thus we get a(15) = 100101001 %p A063697 map(convert, A063696,binary); %Y A063697 Cf. A063699, A063671, A063672. %K A063697 nonn,base %O A063697 0,2 %A A063697 _Antti Karttunen_, Aug 03 2001 %E A063697 a(0) corrected by _Sean A. Irvine_, May 08 2023