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 A306267 #9 Feb 01 2019 17:23:23 %S A306267 1,1,2,3,14,31,230,675,6902,25231,329462,1441923,22934774,116914351, %T A306267 2193664790,12764590275,276054834902,1805409270031,44222780245622, %U A306267 321113303226243,8787513806478134,70146437009397871,2121181056663291350,18462286083671614275 %N A306267 Number of permutations of [n] within distance floor(n/2) of a fixed permutation. %H A306267 Alois P. Heinz, <a href="/A306267/b306267.txt">Table of n, a(n) for n = 0..475</a> %F A306267 a(n) = A306209(n,floor(n/2)). %Y A306267 Cf. A306209. %Y A306267 Shifted bisections give: A048163 (even part), A092552 (odd part). %K A306267 nonn %O A306267 0,3 %A A306267 _Alois P. Heinz_, Feb 01 2019