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 A248948 #18 Apr 09 2021 16:11:48
%S A248948 2,2,0,8,2,5,8,8,1,3,2,8,7,1,7,5,7,0,9,0,8,4,3,4,9,6,8,0,7,3,0,3,4,7,
%T A248948 3,2,6,2,4,5,8,6,8,0,7,4,1,9,8,7,7,0,6,7,6,7,2,7,6,5,9,9,1,5,3,9,8,2,
%U A248948 6,6,2,1,6,3,1,8,6,9,1,9,6,5,4,2,2,4,4,0,5,0,3,4,0,3,0,2,4,2,1,1,3,4,8,1,1
%N A248948 Decimal expansion of Sum_{n >= 1} tan(1/n^2).
%H A248948 Vaclav Kotesovec, <a href="/A248948/b248948.txt">Table of n, a(n) for n = 1..500</a>
%e A248948 2.208258813287175709084349680730347326245868074198770676727659915398266...
%p A248948 evalf(sum(tan(1/n^2), n=1..infinity), 120); # _Vaclav Kotesovec_, Oct 20 2014
%t A248948 (* N[Sum[Tan[1/n^2], {n, 1, Infinity}], 120], yields only 25 correct decimals *)
%o A248948 (PARI) default(realprecision,120); sumpos(n=1,tan(1/n^2)) \\ _Vaclav Kotesovec_, Oct 20 2014
%Y A248948 Cf. A248945, A248946, A248947.
%K A248948 nonn,easy,cons
%O A248948 1,1
%A A248948 _Clark Kimberling_, Oct 18 2014