Number of permutations of length n which avoid the patterns 213, 1234, 4312.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =12a(5) =25a(6) =44a(7) =69a(8) =100a(9) =137a(10) =180a(11) =229a(12) =284a(13) =345a(14) =412a(15) =485a(16) =564a(17) =649a(18) =740a(19) =837a(20) =940a(21) =1049a(22) =1164a(23) =1285a(24) =1412a(25) =1545a(26) =1684a(27) =1829a(28) =1980a(29) =2137