Number of length n permutations avoiding (231,{1},{}) and (132,{},{2}).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =9a(5) =22a(6) =58a(7) =163a(8) =485a(9) =1519a(10) =4985a(11) =17077a(12) =60871a(13) =225152a(14) =862150a(15) =3410641a(16) =13913800a(17) =58440010a(18) =252348913a(19) =1118802690a(20) =5086910935a(21) =23693925911a(22) =112947299251a(23) =550527774738