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 A324365 #10 Feb 24 2019 15:30:36 %S A324365 1,1,2,6,14,53,265,1554,11024,90816,846032,8803826,101011765, %T A324365 1265197857,17167351014,250725968406,3920074915626,65310957981693, %U A324365 1154885557082749,21599009876309400,425919898969718528,8831294211199266816,192065262001816123136 %N A324365 Number of permutations p of [n] having no index i with |p(i)-i| = 3. %H A324365 Alois P. Heinz, <a href="/A324365/b324365.txt">Table of n, a(n) for n = 0..250</a> %H A324365 Wikipedia, <a href="https://en.wikipedia.org/wiki/Permutation">Permutation</a> %F A324365 a(n) = n! - A324366(n). %e A324365 a(4) = 14: 1234, 1243, 1324, 1342, 1423, 1432, 2134, 2143, 2314, 2413, 3124, 3142, 3214, 3412. %Y A324365 Column k=3 of A306512. %Y A324365 Cf. A000142, A324366. %K A324365 nonn %O A324365 0,3 %A A324365 _Alois P. Heinz_, Feb 23 2019