20207880

Appears in sequences

• a(n) = 3^n*A003046(n+1)/A002457(n).at n=6A185149
• Number of unordered quadruples of self-avoiding paths with nodes that cover all vertices of a convex n-gon.at n=11A360275
• Triangle read by rows, T(n, k) = binomial(n, k) * k! * Stirling2(n-k, k), for n >= 0 and 0 <= k <= n//2, where '//' denotes integer division.at n=46A362369
• Table read by rows: T(n, k) = A124320(n + 1, k) * A048993(n, k).at n=40A368584
• Triangle read by rows: T(n,k) is the number of sets of noncrossing paths of size k that cover n nodes arranged in a circle with one node paths disallowed, 0 <= k <= floor(n/2).at n=46A390893