Number of fixed points in all alternating (i.e., down-up) permutations of {1,2,...,n}.

A162978

Number of fixed points in all alternating (i.e., down-up) permutations of {1,2,...,n}.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =4a(4) =15a(5) =52a(6) =257a(7) =1272a(8) =7679a(9) =47864a(10) =346113a(11) =2604380a(12) =22022143a(13) =194053836a(14) =1881735169a(15) =18998097328a(16) =207983607807

External references