21324

Appears in sequences

• Triangle read by rows where the n-th row is the first row of M^n, with M the (n+1)-by-(n+1) matrix with (3,1,3,1,3,1,...) on its main diagonal and (1,3,1,3,1,3,...) on its superdiagonal.at n=38A124573
• Triangle read by rows: T(n,k) is the number of 2-compositions of n having k columns with only nonzero entries (0<=k<=floor(n/2)).at n=39A181307
• Number of length 3+1 0..n arrays with the sum of the maximum of each adjacent pair multiplied by some arrangement of +-1 equal to zero.at n=34A250647
• Total path length of the complete ternary tree of height n.at n=7A289399
• a(n) = A306302(n)/2.at n=22A331756
• Defined by: Sum_{i=1..n} a(i) / n^i = 1, n >= 1.at n=5A374562