Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #19 May 08 2022 22:58:00
%S 1,1,2,6,24,120,720,5038,40004,347348,3165888,29362568,272387290,
%T 2509750674,22933267716,207994616888,1875239211676,16832320088082,
%U 150613964836684,1344743911906806,11988640129482008,106774648037691852,950340529566921394,8454752823292244122
%N The number of permutations of length n that can be sorted by 5 pop stacks in parallel.
%H R. Smith and V. Vatter, <a href="https://www.semanticscholar.org/paper/The-enumeration-of-permutations-sortable-by-pop-in-Smith-Vatter/653c589cffdddc1f6964e1741574742cc7b00546">The enumeration of permutations sortable by pop stacks in parallel</a>
%F G.f.: (-1 -244911168*x^14 +51*x +424049816*x^13 +16848*x^3 -1189*x^2 -162623*x^4 +1135115*x^5 -5933360*x^6 +93180816*x^15 +176551085*x^9 +475936304*x^11 +23718538*x^7 -330046233*x^10 +1620000*x^17 -73376545*x^8 -20032128*x^16 -521745326*x^12)/(9720000*x^17 -68563152*x^16 +235662840*x^15 -511522200*x^14 +774005724*x^13 -859429792*x^12 +721925168*x^11 -467470314*x^10 +235918701*x^9 -93247962*x^8 +28849981*x^7 -6944099*x^6 +1283865*x^5 -178422*x^4 +17989*x^3 -1239*x^2 +52*x -1).
%K nonn,easy
%O 0,3
%A _Vincent Vatter_, Aug 29 2009