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 A317140 #11 Jul 22 2018 14:28:09 %S A317140 1,4,43,906,31493,1629248,117248463,11190963430,1367267690953, %T A317140 208031951035452,38563334673062963,8554779137299629314, %U A317140 2237467931691025532493,681305299577272105281016,238929711424864185326131543,95603626135129502838914478558 %N A317140 Number of permutations of [2n+1] with exactly n increasing runs of length two. %H A317140 Alois P. Heinz, <a href="/A317140/b317140.txt">Table of n, a(n) for n = 0..242</a> %F A317140 a(n) = A317139(2n+1) = A097592(2n+1,n). %F A317140 a(n) + n == 1 (mod 2). %e A317140 a(1) = 4: 132, 213, 231, 312. %Y A317140 Bisection (odd part) of A317139. %Y A317140 Cf. A097592. %K A317140 nonn %O A317140 0,2 %A A317140 _Alois P. Heinz_, Jul 22 2018