a(n) is the number of permutations avoiding 231 and 312 realizable on increasing strict binary trees with 2n-1 nodes.

A245904

a(n) is the number of permutations avoiding 231 and 312 realizable on increasing strict binary trees with 2n-1 nodes.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =22a(4) =84a(5) =330a(6) =1308a(7) =5210a(8) =20796a(9) =83100a(10) =332232a(11) =1328598a(12) =5313732a(13) =21253620a(14) =85011864a(15) =340042246a(16) =1360158564

External references