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 A316389 #18 Jul 03 2018 05:20:35 %S A316389 1,1,2,4,20,2,3,1,6,10,5,2,2,1,2,2,1,18,1,1,3,2,1,2,1,2,1,39,2,1,1,1, %T A316389 13,1,2,1,30,1,1,1,3,2,5,4,1,5,1,5,1,2,1,1,94,6,2,19,11,1,60,1,1,50,2, %U A316389 1,1,8,53,1,3,1,6,3,2,1,5,1,1,3,4,636,1,2,1,3,3,7,9,1,2,10,3,1,22,1,119,3,32,1,2,1 %N A316389 Continued fraction expansion of largest root of x^3 - 7*x + 7. %C A316389 a(n) is identical to A039921(n-1) for n >= 3. The largest root of x^3 - 7*x + 7 equals (3*w-1)/(2*w-1) for w = 2*cos(Pi/7), where w is the number referenced in A039921. Interestingly enough, all three roots of x^3-7*x+7 have a continued fraction expansion that ends in 2, 3, 1, 6, 10, 5, 2, 2, 1, ... which is a(n) for n >= 5. %e A316389 1.69202147163009586962781489700206914019726... %t A316389 ContinuedFraction[Root[x^3 - 7 x + 7, 3], 100] %Y A316389 Cf. A039921. %K A316389 nonn,cofr %O A316389 1,3 %A A316389 _Greg Dresden_, Jul 01 2018