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 A382907 #10 Aug 08 2025 03:13:57
%S A382907 0,2,5,9,7,0,2,7,5,5,1,5,7,4,0,0,3,2,1,5,7,5,9,2,2,2,6,6,6,6,2,3,7,7,
%T A382907 1,3,5,7,4,2,6,3,0,5,6,9,5,3,0,7,5,2,4,7,2,4,6,2,2,8,7,3,7,5,4,5,9,8,
%U A382907 4,3,0,0,0,3,8,3,9,4,8,1,8,1,7,4,7,8,9
%N A382907 Decimal expansion of 1/2 - Pi*(sqrt(2)+1)/16.
%H A382907 I. S. Gradsteyn and I. M. Ryzhik, <a href="http://mathtable.com/gr/index.html">Table of integrals, series and products</a> (6th ed.), 2000, (eq. 0.239.7).
%F A382907 Equals Sum_{k>=1} 1/((8*k-1)*(8*k+1)).
%F A382907 From _Amiram Eldar_, Aug 08 2025: (Start)
%F A382907 Equals Sum_{k>=1} 1/A158684(k).
%F A382907 Equals (1 - cot(Pi/8)*Pi/8)/2. (End)
%e A382907 0.02597027551574003215759...
%t A382907 Join[{0},RealDigits[1/2-(Pi(Sqrt[2]+1))/16,10,120][[1]]] (* _Harvey P. Dale_, Apr 30 2025 *)
%Y A382907 Cf. A158684, A239120.
%K A382907 nonn,cons
%O A382907 0,2
%A A382907 _Sean A. Irvine_, Apr 08 2025