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 A291715 #11 Sep 16 2017 15:00:39 %S A291715 210,252,280,315,336,350,360,420 %N A291715 a(n) = 420*(preferred ratios of room width / height in Alberti's Ten Books on Architecture). %H A291715 Radislav Zuk, <a href="https://doi.org/10.1007/978-3-319-00137-1_38">From Renaissance Musical Proportions to Polytonality in Twentieth Century Architecture</a>, Chapter 38 in Volume 1 of K. Williams and M. J. Ostwald (eds.), Architecture and Mathematics from Antiquity to the Future, DOI 10.1007/978-3-319-00137-1_38, Springer International Publishing Switzerland 2015 %e A291715 a(5)=336 is in the sequence, because the height / width ratio of 420 / 336 corresponds to the preferred ratio of H:W = 5:4 provided in the table given in A291713. %Y A291715 Cf. A291713, A291714, A291719. %K A291715 nonn,fini,full %O A291715 1,1 %A A291715 _Hugo Pfoertner_, Sep 01 2017