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 A369500 #8 Jan 25 2024 03:58:12
%S A369500 4,5,3,2,3,6,0,1,4,1,8,3,4,9,6,8,7,0,2,1,4,2,4,6,8,9,8,7,9,2,8,9,6,4,
%T A369500 7,3,7,8,6,9,7,3,8,6,7,7,3,7,9,1,1,8,4,2,4,8,0,2,7,3,0,0,3,2,0,5,5,5,
%U A369500 0,3,6,4,8,8,3,6,7,1,5,3,5,8,2,6,2,5,4,2,0,3,0,9,1,2,6,2,6,0,6,2,1,6,5,1,7
%N A369500 Decimal expansion of Sum_{k=-oo..oo} 1/(2^(k/2)+2^(-k/2)).
%C A369500 Larger than Pi/log(2) by less than 10^(-11).
%H A369500 Gérard Maze and Lorenz Minder, <a href="https://doi.org/10.4171/em/61">A new family of almost identities</a>, Elemente der Mathematik, Vol. 62, No. 3 (2007), pp. 89-97.
%F A369500 Equals (Pi/log(2)) * (1 + 2 * Sum_{k>=1} sech(2*k*Pi^2/log(2))).
%e A369500 4.5323601418349687021424689879289647378697386773791184248...
%t A369500 RealDigits[Chop[N[Sum[1/(2^(k/2) + 2^(-k/2)), {k, -Infinity, Infinity}], 120]]][[1]]
%o A369500 (PARI) (Pi/log(2)) * (1 + 2 * sumpos(k = 1, 1/cosh(2*k*Pi^2/log(2))))
%Y A369500 Cf. A163973.
%K A369500 nonn,cons
%O A369500 1,1
%A A369500 _Amiram Eldar_, Jan 25 2024