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 A081359 #7 Jan 14 2013 02:22:04 %S A081359 6,7,10,16,25 %N A081359 Problem 49 on page 235 of "Mathematics", California Edition, by Carole Greenes et al. %C A081359 Several different books match the description, e.g. ISBN 978-0618081776 and ISBN 978-0618081790. The precise definition remains a mystery. %D A081359 Carole Greenes, Miriam A. Leiva, Bruce R. Vogeli (et al.?), "Mathematics, California Edition", various editions published by Houghton Mifflin Company. %K A081359 nonn,unkn %O A081359 0,1 %A A081359 Joe T. Hoang (HoangJoe(AT)yahoo.com), Mar 18 2003 %E A081359 Edited by _M. F. Hasler_, Mar 27 2008