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 A324366 #8 Feb 24 2019 15:30:17 %S A324366 0,0,0,0,10,67,455,3486,29296,272064,2782768,31112974,377989835, %T A324366 4961822943,70010940186,1056948399594,17002714972374,290376470114307, %U A324366 5247488148645251,100046090532522600,2006982109206921472,42259647960510173184,931935465775791556864 %N A324366 Number of permutations p of [n] having at least one index i with |p(i)-i| = 3. %H A324366 Alois P. Heinz, <a href="/A324366/b324366.txt">Table of n, a(n) for n = 0..250</a> %H A324366 Wikipedia, <a href="https://en.wikipedia.org/wiki/Permutation">Permutation</a> %F A324366 a(n) = n! - A324365(n). %e A324366 a(4) = 10: 2341, 2431, 3241, 3421, 4123, 4132, 4213, 4231, 4312, 4321. %Y A324366 Column k=3 of A306506. %Y A324366 Cf. A000142, A324365. %K A324366 nonn %O A324366 0,5 %A A324366 _Alois P. Heinz_, Feb 23 2019