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Decimal expansion of sum_{n >= 1} (tan(2/n))^2.
1

%I #12 Oct 20 2014 18:10:06

%S 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 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 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 Decimal expansion of sum_{n >= 1} (tan(2/n))^2.

%H Vaclav Kotesovec, <a href="/A248951/b248951.txt">Table of n, a(n) for n = 1..500</a>

%e 9.0435286086582111526563827472958995791513335719871504139242512780719363...

%p evalf(sum((tan(2/n))^2, n=1..infinity), 120); # _Vaclav Kotesovec_, Oct 20 2014

%t (* N[Sum[Tan[2/n]^2, {n, 1, Infinity}], 120], yields only 24 correct decimals *)

%o (PARI) default(realprecision,120); sumpos(n=1,(tan(2/n))^2) \\ _Vaclav Kotesovec_, Oct 20 2014

%Y Cf. A248946, A248947, A248948, A248950.

%K nonn,easy,cons

%O 1,1

%A _Clark Kimberling_, Oct 18 2014