Number of set partitions of [n] avoiding the patterns {1123, 1211}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =13a(5) =33a(6) =81a(7) =196a(8) =470a(9) =1126a(10) =2699a(11) =6487a(12) =15633a(13) =37788a(14) =91589a(15) =222572a(16) =542145a(17) =1323446a(18) =3237074a(19) =7932108a(20) =19469151a(21) =47860083a(22) =117819348a(23) =290424126a(24) =716772644a(25) =1771035921a(26) =4380646788a(27) =10846386691a(28) =26880759090a(29) =66678169061