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 A254140 #9 Feb 16 2025 08:33:24 %S A254140 2,9,7,3,2,0,9,5,9,8,2,4,7,3,7,8,7,0,2,5,2,8,1,8,5,6,6,7,6,3,9,5,7,1, %T A254140 7,9,8,0,1,9,7,4,5,4,7,9,2,1,0,6,1,0,8,7,8,7,7,7,6,0,9,4,5,0,6,2,5,8, %U A254140 6,5,4,3,2,2,7,1,9,6,1,6,3,2,8,6,7,6,4,4,1,8,8,5,3,7,5,0,2,0,7,4,4,4,6,9,4 %N A254140 Decimal expansion of the average reciprocal distance between two points chosen at random in a unit square. %H A254140 D. H. Bailey, J. M. Borwein, R. E. Crandall, <a href="http://dx.doi.org/10.1090/S0025-5718-10-02338-0">Advances in the theory of box integrals</a> Math. Comp. 79 (2010), 1839-1866, p. 24. %H A254140 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/SquareLinePicking.html">Square Line Picking</a> %F A254140 Integral over a unit square of 1/sqrt((r1-q1)^2 + (r2-q2)^2) dr1 dr2 dq1 dq2 = 4/3 - 4*sqrt(2)/3 + 4*log(1 + sqrt(2)). %e A254140 2.97320959824737870252818566763957179801974547921061 ... %t A254140 RealDigits[4/3 - 4*Sqrt[2]/3 + 4*Log[1 + Sqrt[2]], 10, 105] // First %Y A254140 Cf. A091505. %K A254140 nonn,cons,easy %O A254140 1,1 %A A254140 _Jean-François Alcover_, Jan 26 2015