Cardinality of the set of equivalence classes of the set X_n of finite integer sequences {x_1 = 0, x_2, ..., x_n} satisfying |x_k - x_{k+1}| = 1, where two such sequences are deemed equivalent if they are permutations of each other.

A254007

Cardinality of the set of equivalence classes of the set X_n of finite integer sequences {x_1 = 0, x_2, ..., x_n} satisfying |x_k - x_{k+1}| = 1, where two such sequences are deemed equivalent if they are permutations of each other.