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 A039931 #20 Mar 05 2020 03:16:58 %S A039931 1,2,2,5,2,5,2,14,6,5,2,23,2,5,5,61,2,26,2,35,5,5,2 %N A039931 Number of different sets of parameters for mixed orthogonal arrays with n runs and strength 2. %C A039931 a(36) is the first unknown term. %D A039931 A. S. Hedayat, N. J. A. Sloane and J. Stufken, Orthogonal Arrays, Springer-Verlag, NY, 1999. %H A039931 E. M. Rains, N. J. A. Sloane and J. Stufken, The Lattice of N-Run Orthogonal Arrays, J. Stat. Planning Inference, 102 (2002), 477-500 (<a href="http://neilsloane.com/doc/rao.txt">Abstract</a>, <a href="http://neilsloane.com/doc/rao.pdf">pdf</a>, <a href="http://neilsloane.com/doc/rao.ps">ps</a>). %H A039931 Eric D. Schoen, Pieter T. Eendebak and Man V. M. Nguyen, <a href="https://doi.org/10.1002/jcd.20236">Complete enumeration of pure-level and mixed-level orthogonal arrays</a>, Journal of Combinatorial Designs, Volume 18, Issue 2, pages 123-140, March 2010; DOI: 10.1002/jcd.20236; <a href="https://doi.org/10.1002/jcd.20270">Correction</a>: Journal of Combinatorial Designs, Volume 18, Issue 6, page 488, November 2010; DOI: 10.1002/jcd.20270. %e A039931 For 12 runs there are 23 different sets of parameters: 12^1, 2^k with 1 <= k <= 11, 3^1*2^k with 0 <= k <= 4, 6^1*2^k with 0 <= k <= 2, 4^1*3^1, 4^1 and 1^1. %Y A039931 Cf. A039927, A039930. %K A039931 nonn,nice,more %O A039931 1,2 %A A039931 _N. J. A. Sloane_ %E A039931 Needs to be updated using the results of Schoen et al. (2010). - _N. J. A. Sloane_, Feb 21 2013