Number of permutations of length n which avoid the patterns 321, 1324, 2341.

Terms

a(0) =1a(1) =2a(2) =5a(3) =12a(4) =24a(5) =41a(6) =63a(7) =90a(8) =122a(9) =159a(10) =201a(11) =248a(12) =300a(13) =357a(14) =419a(15) =486a(16) =558a(17) =635a(18) =717a(19) =804a(20) =896a(21) =993a(22) =1095a(23) =1202a(24) =1314a(25) =1431a(26) =1553a(27) =1680a(28) =1812a(29) =1949