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Decimal expansion of Sum_{n>=0} 1/cosh(n).
3

%I #16 May 19 2022 08:07:23

%S 2,0,7,1,1,2,1,3,2,9,9,6,7,8,2,3,1,6,9,5,7,1,5,7,2,9,9,2,6,8,3,5,2,6,

%T 2,6,0,8,9,3,7,9,4,6,5,8,3,0,6,9,3,0,7,5,5,8,1,5,6,5,0,6,6,1,1,1,4,4,

%U 5,1,2,2,6,6,1,2,2,6,2,9,3,7,3,2,7,1,2,5,0,0,2,2,2,9,5,0,5,2,8,5,5,6,4,6,7

%N Decimal expansion of Sum_{n>=0} 1/cosh(n).

%e 2.071121329967823169571572992683526260893794658306930755815650661114451...

%p evalf(sum(1/cosh(n), n = 0..infinity), 120);

%t RealDigits[N[Re[Sum[1/Cosh[n],{n,0,Infinity}]],110],10,105][[1]]

%o (PARI) suminf(n=0, 1/cosh(n)) \\ _Michel Marcus_, Jan 30 2015

%Y Cf. A185393, A254446, A335415.

%K nonn,cons

%O 1,1

%A _Vaclav Kotesovec_, Jan 30 2015