Number of permutations of the multiset {1,1,1,1,2,2,2,2,3,3,3,3,...,n,n,n,n} with no two consecutive terms equal.

A321633

Number of permutations of the multiset {1,1,1,1,2,2,2,2,3,3,3,3,...,n,n,n,n} with no two consecutive terms equal.

Terms

    a(0) =1a(1) =0a(2) =2a(3) =1092a(4) =2265024a(5) =11804626080

External references