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 A214611 #25 Jun 18 2024 15:41:17 %S A214611 1,2,6,24,120,685,4148,25661,159829,997870,6240672,39111747,245782289, %T A214611 1549368610 %N A214611 Number of permutations of length n sortable by a pop stack followed by a queue and then by a stack. %H A214611 R. Smith and V. Vatter, <a href="https://ajc.maths.uq.edu.au/pdf/58/ajc_v58_p157.pdf">A stack and a pop stack in series</a>, The Australasian Journal of Combinatorics, Volume 58(1) (2014), pp. 157-171. %e A214611 There are only a(6)=685 permutations of length 6 that can be sorted by this machine; the machine can sort all shorter permutations. %Y A214611 Cf. A033321. %K A214611 nonn,hard,more %O A214611 1,2 %A A214611 _Vincent Vatter_, Mar 06 2013 %E A214611 a(11)-a(14) from _Bert Dobbelaere_, Jun 18 2024