Number of cycle-up-down permutations of {1,2,...,n} having no fixed points. A permutation is said to be cycle-up-down if it is a product of up-down cycles. A cycle (b(1), b(2), ...) is said to be up-down if, when written with its smallest element in the first position, it satisfies b(1)<b(2)>b(3)<... .

A186364

Number of cycle-up-down permutations of {1,2,...,n} having no fixed points. A permutation is said to be cycle-up-down if it is a product of up-down cycles. A cycle (b(1), b(2), ...) is said to be up-down if, when written with its smallest element in the first position, it satisfies b(1)<b(2)>b(3)<... .

Terms

    a(0) =1a(1) =0a(2) =1a(3) =1a(4) =5a(5) =15a(6) =71a(7) =341a(8) =1945a(9) =12135a(10) =84091a(11) =635281a(12) =5212085a(13) =46091955a(14) =437198711a(15) =4426839821a(16) =47657861425a(17) =543551916975

External references