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 A260016 #15 Dec 27 2017 10:42:10 %S A260016 3,2,7,13,21,41,91,269,419,921,2983,8519,18859,53611,136631,436341 %N A260016 Smallest number requiring n digits for its representation in the "Terrible Twos Problem" without using multidigit expressions. %D A260016 C. Pickover, Mazes for the Mind, St. Martin's Press, NY, 1992, p. 376. %D A260016 C. Pickover, "Wonders of Numbers", Chapter 78, 'Creator Numbers', Oxford University Press, NY, 2001. pp. 187-189, 343-345. %H A260016 C. Pickover, <a href="/A260016/a260016.pdf">"The Terrible Twos Problem", Chapter 73, 'Mazes for the Mind'</a>, St. Martin's Press, NY, 1992, p. 373-377. (Annotated scanned copy) %Y A260016 Cf. A060273. %K A260016 nonn,more %O A260016 2,1 %A A260016 _N. J. A. Sloane_, Jul 13 2015, following a suggestion from _Robert G. Wilson v_, Aug 25 1983