OFFSET
0,5
COMMENTS
Let M be the tangent matrix of dimension n X n. The definition of the tangent matrix is given in A346831. An Euler permutation of order n is a permutation sigma of {1,...,n} if P = Product_{k=1..n} M(k, sigma(k)) does not vanish. We say sigma is a positive Euler permutation of order n (or sigma in EP(n)) if P = 1 and a negative Euler permutation of order n (or sigma in EN(n)) if P = -1.
FORMULA
MAPLE
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Sep 10 2021
STATUS
approved