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 A351831 #17 Feb 21 2022 07:23:58 %S A351831 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,70 %N A351831 Vector in the 26-dimensional even Lorentzian unimodular lattice II_25,1 used to construct the Leech lattice. %C A351831 As noted by Conway and Sloane (1999), the only nontrivial solution of 0^2 + 1^2 + ... + m^2 = n^2 in positive integers is m = 24, n = 70, allowing them to use the vector (0, 1, 2, 3, ..., 23, 24 | 70) to construct the Leech lattice. %H A351831 Richard E. Borcherds, <a href="https://www.youtube.com/watch?v=ycpmMnO3-Uk">How to construct the Leech lattice</a>, YouTube video, 2022. %H A351831 J. H. Conway and N. J. A. Sloane, <a href="https://doi.org/10.1090/S0273-0979-1982-14985-0">Lorentzian forms for the Leech lattice</a>, Bulletin (New Series) of the American Mathematical Society, Volume 6, Number 2, March 1982. %H A351831 J. H. Conway and N. J. A. Sloane, <a href="https://doi.org/10.1007/978-1-4757-6568-7">Sphere Packings, Lattices and Groups</a>, 3rd edition, Springer, New York, NY, 1999, pp. 524-528. %H A351831 Wikipedia, <a href="https://en.wikipedia.org/wiki/II25,1">II_25,1</a>. %H A351831 Wikipedia, <a href="https://en.wikipedia.org/wiki/Leech_lattice">Leech lattice</a>. %t A351831 Append[Range[0,24],70] %Y A351831 Cf. A008408, A260646, A351830. %K A351831 nonn,easy,fini,full %O A351831 1,3 %A A351831 _Paolo Xausa_, Feb 21 2022