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 A248951 #12 Oct 20 2014 18:10:06
%S A248951 9,0,4,3,5,2,8,6,0,8,6,5,8,2,1,1,1,5,2,6,5,6,3,8,2,7,4,7,2,9,5,8,9,9,
%T A248951 5,7,9,1,5,1,3,3,3,5,7,1,9,8,7,1,5,0,4,1,3,9,2,4,2,5,1,2,7,8,0,7,1,9,
%U A248951 3,6,3,4,5,9,9,6,4,4,8,8,9,4,6,7,5,4,6,4,2,4,8,4,7,2,8,5,9,7,0,9,8,5,2,2,4
%N A248951 Decimal expansion of sum_{n >= 1} (tan(2/n))^2.
%H A248951 Vaclav Kotesovec, <a href="/A248951/b248951.txt">Table of n, a(n) for n = 1..500</a>
%e A248951 9.0435286086582111526563827472958995791513335719871504139242512780719363...
%p A248951 evalf(sum((tan(2/n))^2, n=1..infinity), 120); # _Vaclav Kotesovec_, Oct 20 2014
%t A248951 (* N[Sum[Tan[2/n]^2, {n, 1, Infinity}], 120], yields only 24 correct decimals *)
%o A248951 (PARI) default(realprecision,120); sumpos(n=1,(tan(2/n))^2) \\ _Vaclav Kotesovec_, Oct 20 2014
%Y A248951 Cf. A248946, A248947, A248948, A248950.
%K A248951 nonn,easy,cons
%O A248951 1,1
%A A248951 _Clark Kimberling_, Oct 18 2014