23895673

Appears in sequences

• Number of balanced parenthesis expressions of length 2n and depth 3.at n=16A258109
• a(n) = a(n-1) + 3*a(n-2) -2*a(n-3) - 2*a(n-4), where a(0) = 0, a(1) = 0, a(2) = 1, a(3) = 2.at n=34A295724