cp's OEIS Frontend

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.

A133741 Decimal expansion of offset at which two unit disks overlap by half each's area.

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%I A133741 #27 Feb 16 2025 08:33:06
%S A133741 8,0,7,9,4,5,5,0,6,5,9,9,0,3,4,4,1,8,6,3,7,9,2,3,4,8,0,1,3,2,6,3,0,8,
%T A133741 8,5,8,0,4,4,7,1,9,2,9,1,4,8,1,9,6,8,4,4,5,0,0,1,9,5,2,0,3,4,6,7,7,4,
%U A133741 1,0,9,9,9,4,2,5,9,0,7,0,7,0,0,2,4,8,6,7,8,0,3,3,0,4,4,5,4,5,7,4,1,8,9,8,2
%N A133741 Decimal expansion of offset at which two unit disks overlap by half each's area.
%H A133741 G. C. Greubel, <a href="/A133741/b133741.txt">Table of n, a(n) for n = 0..10000</a>
%H A133741 Max Chicky Fang, <a href="https://arxiv.org/abs/2403.10529">Closed Form for Half-Area Overlap Offset of 2 Unit Disks</a>, arXiv:2403.10529 [math.GM], 2024.
%H A133741 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Circle-CircleIntersection.html">Circle-Circle Intersection</a>
%F A133741 Equals sqrt(1+A003957) - sqrt(1-A003957) = sqrt(2-2*sqrt(1-A003957^2)) = 2*A086751. - _Gleb Koloskov_, Feb 26 2021
%e A133741 0.8079455065990344186379234801326308858044719291481968445...
%t A133741 d0 = d /. FindRoot[ 2*ArcCos[d/2] - d/2*Sqrt[4 - d^2] == Pi/2, {d, 1}, WorkingPrecision -> 110]; RealDigits[d0][[1]][[1 ;; 105]] (* _Jean-François Alcover_, Oct 26 2012, after _Eric W. Weisstein_ *)
%o A133741 (PARI) default(realprecision, 100); solve(x=0,1, 2*acos(x/2) - (x/2)*sqrt(4-x^2) - Pi/2) \\ _G. C. Greubel_, Nov 16 2018
%o A133741 (PARI) d=solve(x=0,1,cos(x)-x);sqrt(2-2*sqrt(1-d^2)) \\ _Gleb Koloskov_, Feb 27 2021
%Y A133741 Cf. A003957. Equals twice A086751.
%K A133741 nonn,cons
%O A133741 0,1
%A A133741 _Eric W. Weisstein_, Sep 22 2007