Number of length n permutations avoiding (132,{2},{}) and (123,{},{1}).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =9a(5) =22a(6) =57a(7) =156a(8) =447a(9) =1335a(10) =4140a(11) =13290a(12) =44055a(13) =150494a(14) =528860a(15) =1909010a(16) =7068879a(17) =26820161a(18) =104156616a(19) =413634176a(20) =1678323602a(21) =6952182325a(22) =29378908664a(23) =126568357635a(24) =555540596435