Number of graceful permutations of length n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =4a(5) =8a(6) =24a(7) =32a(8) =40a(9) =120a(10) =296a(11) =648a(12) =1328a(13) =3200a(14) =9912a(15) =25592a(16) =55920a(17) =143192a(18) =510696a(19) =1451296a(20) =3497344a(21) =10451824a(22) =38570704a(23) =118914992a(24) =315235872a(25) =1014824752a(26) =3963684496a(27) =13166130152a(28) =37846301904a(29) =130507967088