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 A020505 #15 Feb 26 2024 10:59:34
%S A020505 -6,-7,-5,31,37,1111,43,39991,1297,46441,1555,51828151,1261,
%T A020505 1865813431,55987,1950271,1679617,2418094206391,46873,87051391430071,
%U A020505 1634221,2527867231,72559411,112818603293371831,1678321
%N A020505 Cyclotomic polynomials at x=-6.
%H A020505 Paolo Xausa, <a href="/A020505/b020505.txt">Table of n, a(n) for n = 0..1000</a>
%H A020505 <a href="/index/Cy#CyclotomicPolynomialsValuesAtX">Index entries for cyclotomic polynomials, values at X</a>
%p A020505 with(numtheory,cyclotomic); f := n->subs(x=-6,cyclotomic(n,x)); seq(f(i),i=0..64);
%t A020505 Join[{-6}, Cyclotomic[Range[50], -6]] (* _Paolo Xausa_, Feb 26 2024 *)
%K A020505 sign
%O A020505 0,1
%A A020505 _Simon Plouffe_