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 A051559 #11 Nov 05 2017 21:55:32
%S A051559 0,2,7,4,2,2,4,3,8,4,8,2,0,9,7,7,6,8,5,8,3,2,8,7,9,9,1,8,7,1,1,8,6,6,
%T A051559 0,6,4,6,6,7,2,0,7,2,6,3,1,3,6,1,4,5,0,1,5,6,2,2,9,4,4,5,5,1,9,2,9,5,
%U A051559 4,8,0,5,9,0,0,4,5,1,9,8,2,2,8,8,9,4,6,0,3,5,2,8,9,9,9,9,8,6,6
%N A051559 Decimal expansion of tan(Pi/2 degrees). (Of course, tan(Pi/2 radians) = infinity.)
%e A051559 0.027422438...
%p A051559 evalf(tan(Pi^2/360)) ;
%t A051559 Join[{0},RealDigits[Tan[Pi/2 Degree],10,120][[1]]] (* _Harvey P. Dale_, Sep 05 2015 *)
%o A051559 (PARI) tan(Pi^2/360) \\ _Charles R Greathouse IV_, Nov 05 2017
%Y A051559 Cf. A051553-A051555, A051557, A051558.
%K A051559 nonn,easy,cons
%O A051559 0,2
%A A051559 _N. J. A. Sloane_