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 A182565 #20 Oct 13 2023 07:36:12 %S A182565 4,4,4,2,4,7,5,2,0,9,8,3,8,9,5,5,4,8,7,1,4,0,9,2,2,6,8,0,7,3,6,0,0,2, %T A182565 3,8,1,2,5,6,8,7,5,4,4,9,5,5,9,9,8,6,2,7,9,3,8,6,1,1,7,4,2,8,2,4,4,3, %U A182565 0,9,5,6,1,2,5,7,9,4,9,8,9,4,7,1,8,0,6,2,5,2,6,2,2,5,9,4,1,9,8,6,8,7,0,3,4 %N A182565 Decimal expansion of Madelung constant (negated) for cuprous oxide Cu_2O. %H A182565 Leslie Glasser, <a href="https://doi.org/10.1021/ic2023852">Solid-State Energetics and Electrostatics: Madelung Constants and Madelung Energies</a>, Inorg. Chem., 2012, 51 (4), 2420-2424. %H A182565 Yosio Sakamoto, <a href="https://doi.org/10.1063/1.1744060">Madelung Constants of Simple Crystals Expressed in Terms of Born's Basic Potentials of 15 Figure</a>, The Journal of Chemical Physics 28, 164 (1958). See Table III, row C3, column M_r. %H A182565 Wikipedia, <a href="https://en.wikipedia.org/wiki/Copper(I)_oxide">Copper(I) oxide</a>. %F A182565 Equals (sqrt(3)/4) * (2 * A085469 + 3 * (A185577 + A185578)). [Sakamoto] - _Andrey Zabolotskiy_, Oct 12 2023 %e A182565 -4.4424752098389... %Y A182565 Cf. A085469, A181152, A182566, A182567, A185577, A185578. %K A182565 nonn,cons %O A182565 1,1 %A A182565 _N. J. A. Sloane_, May 05 2012 %E A182565 More terms using the formula added by _Andrey Zabolotskiy_, Oct 12 2023