Number of permutations of length n which avoid the patterns 1243, 2341, 4132.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =73a(5) =239a(6) =740a(7) =2199a(8) =6348a(9) =17947a(10) =49954a(11) =137372a(12) =374164a(13) =1011303a(14) =2716439a(15) =7259970a(16) =19324340a(17) =51268390a(18) =135658217a(19) =358193704a(20) =944162051a(21) =2485297822a(22) =6534794291a(23) =17167312441a(24) =45067797703a(25) =118245785494