-21318

Appears in sequences

• Number triangle T(n,k)=(-1)^(n-k)*(3k+2)*C(3n+1, n-k)/(2n+k+2).at n=28A124821
• Triangle read by rows: T(n,m) = (m/(n-m))*Sum_{k=1..n-m}((-1)^k*binomial(m-1,k-1)*binomial(3*(n-m)-k-1,n-m-k)), T(n,n)=1.at n=36A271460