cp's OEIS Frontend

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.

A377968 Decimal expansion of tan(arctan(4)/4).

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%I A377968 #14 Nov 20 2024 23:51:24
%S A377968 3,4,4,1,5,0,7,3,1,4,0,8,9,1,0,8,0,7,7,1,4,7,5,9,2,2,7,8,8,5,3,4,6,8,
%T A377968 4,7,6,0,5,6,5,0,2,0,8,3,2,5,8,4,4,0,5,8,2,4,5,8,1,7,5,1,4,8,8,0,4,5,
%U A377968 4,0,1,0,7,8,2,8,3,5,8,4,0,3,4,3,3,3,0,5,1,0
%N A377968 Decimal expansion of tan(arctan(4)/4).
%H A377968 Michael Penn, <a href="https://www.youtube.com/watch?v=bZ5xLepCFZk">A beautiful identity</a>, YouTube video, 2024.
%H A377968 <a href="/index/Al#algebraic_04">Index entries for algebraic numbers, degree 4</a>
%F A377968 Equals 2*(cos(6*Pi/17) + cos(10*Pi/17)) = 2*(cos(6*A019684) + cos(10*A019684)).
%F A377968 Equals (sqrt(34 + 2*sqrt(17)) - sqrt(17) - 1)/4 = (sqrt(34 + 2*A010473) - A010473 - 1)/4.
%F A377968 Equals the root closest to 0 of x^4 + x^3 - 6*x^2 - x + 1.
%e A377968 0.34415073140891080771475922788534684760565020832584...
%t A377968 First[RealDigits[Tan[ArcTan[4]/4], 10, 100]]
%Y A377968 Cf. A010473, A019684, A195628.
%K A377968 nonn,cons,easy
%O A377968 0,1
%A A377968 _Paolo Xausa_, Nov 13 2024