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 A293774 #17 Oct 21 2017 22:02:52 %S A293774 1,1,2,6,24,88,303,1033,3544,12220,42164,145364,500954,1726408, %T A293774 5950050,20507364,70680192,243602952,839588620,2893682172,9973219220, %U A293774 34373198420,118468937648,408309065104,1407257423576,4850182474912 %N A293774 Number of permutations of length n sortable by 3 passes through a pop-stack. %H A293774 Bjarki Ágúst Guðmundsson, <a href="/A293774/b293774.txt">Table of n, a(n) for n = 0..1000</a> %H A293774 Anders Claesson, Bjarki Ágúst Guðmundsson, <a href="https://arxiv.org/abs/1710.04978">Enumerating permutations sortable by k passes through a pop-stack</a>, arXiv:1710.04978 [math.CO], 2017. %F A293774 G.f.: (2*x^10 + 4*x^9 + 2*x^8 + 5*x^7 + 11*x^6 + 8*x^5 + 6*x^4 + 6*x^3 + 2*x^2 + x - 1) / (4*x^10 + 8*x^9 + 4*x^8 + 10*x^7 + 22*x^6 + 16*x^5 + 8*x^4 + 6*x^3 + 2*x^2 + 2*x - 1). %o A293774 (PARI) Vec((2*x^10 + 4*x^9 + 2*x^8 + 5*x^7 + 11*x^6 + 8*x^5 + 6*x^4 + 6*x^3 + 2*x^2 + x - 1)/(4*x^10 + 8*x^9 + 4*x^8 + 10*x^7 + 22*x^6 + 16*x^5 + 8*x^4 + 6*x^3 + 2*x^2 + 2*x - 1) + O(x^30)) %Y A293774 Cf. A224232, A293775, A293776, A293784. %K A293774 nonn,easy %O A293774 0,3 %A A293774 _Bjarki Ágúst Guðmundsson_, Oct 16 2017