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 A246251 #10 Aug 26 2014 17:03:44 %S A246251 1488257158851,176902009674966,13166075391964578,775944032960346939, %T A246251 39844140679287441918,1872063201155821139178,82897279832156950225548, %U A246251 3526803545750650310760216,146090377422354615989531688,5948505245302032452585146020,239776137775416266444362226760 %N A246251 Number of permutations of [n] with exactly six occurrences of the consecutive step pattern up, down, down. %H A246251 Alois P. Heinz, <a href="/A246251/b246251.txt">Table of n, a(n) for n = 19..160</a> %F A246251 a(n) ~ c * (3*sqrt(3)/(2*Pi))^n * n! * n^6, where c = 0.000003054026651631929902... = c0 * (c0-1)^6 / (3^6 * 6!), and c0 = (1 + exp(Pi/sqrt(3))) * sqrt(3) / (2*Pi). - _Vaclav Kotesovec_, Aug 26 2014 %Y A246251 Column k=6 of A242819. %K A246251 nonn %O A246251 19,1 %A A246251 _Alois P. Heinz_, Aug 20 2014