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 A006948 M1255 #18 Jan 01 2023 04:28:03 %S A006948 1,2,4,12,30,90,244,776,2218,6946,20468 %N A006948 Number of zero-entropy permutations of length n. %D A006948 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A006948 A. Blokh, E. Coven, and L. Block, <a href="http://people.cas.uab.edu/~ablokh/zeren1.pdf">Zero Entropy Permutations</a>, International Journal of Bifurcation and Chaos 5 (1995), 1331-1337. %K A006948 nonn,more %O A006948 1,2 %A A006948 Ethan Coven (ecoven(AT)wesleyan.edu) %E A006948 a(6) corrected and a(7)-a(11) from _Sean A. Irvine_, Sep 27 2017