Number of signed permutations of length n+2 with adjacent elements differing by more than 1 whose first element is 1 and whose last element has absolute value n+2.

A370768

Number of signed permutations of length n+2 with adjacent elements differing by more than 1 whose first element is 1 and whose last element has absolute value n+2.

Terms

    a(0) =1a(1) =1a(2) =5a(3) =29a(4) =249a(5) =2553a(6) =31181a(7) =441845a(8) =7133569a(9) =129304593a(10) =2600559125a(11) =57473713741

External references