3421710

Appears in sequences

• Super ballot numbers: 6(2n)!/(n!(n+2)!).at n=15A007054
• a(n) = 6*(2n-4)!/((n-2)!n!), if n>2. a(0) = 1, a(1) = a(2) = 2.at n=17A091712
• a(n) = A184879(2*n, n) - A184879(2*n, n+1) where A184879(n, k) = Hypergeometric2F1(-2*k, 2*k-2*n, 1, -1) if 0<=k<=n.at n=16A184881