%I #25 Apr 21 2021 11:59:56
%S 9,8,0,8,5,4,2,7,4,5,9,1,3,5,0,6,1,5,3,9,2,2,3,2,2,7,8,2,9,9,0,1,9,6,
%T 2,2,1,1,8,5,4,1,8,0,0,7,2,0,2,3,2,0,3,6,0,6,9,7,9,0,4,2,6,4,1,3,8,8,
%U 6,4,9,3,6,2,7,7,1,9,2,0,0,7,4,3,6,1,0,6,5,8,7,1
%N Decimal expansion of Sum_{n>=1} (-1)^(n-1)/(n*arctan(n)).
%C The alternating series test shows this series is convergent.
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Alternating_series_test">Alternating series test</a>.
%F Equals Sum_{n>=1} (-1)^(n-1)/(n*arctan(n)).
%e 0.98085427459135061539223227829901962211854180072023203606979...
%p evalf(sum((-1)^(n-1)/(n*arctan(n)), n=1..infinity),120);
%o (PARI) sumalt(n=1, (-1)^(n-1)/(n*atan(n))) \\ _Michel Marcus_, Apr 16 2021
%Y Cf. A343470, A265011.
%K nonn,cons
%O 0,1
%A _Bernard Schott_, Apr 16 2021