399429602

Appears in sequences

• Convolution of A000108 (Catalan numbers) with A020922.at n=9A045530
• a(0) = 0, thereafter, a(n) = 2^(2*n-1)*( binomial((3*n-1)/2,n) - binomial(3*n/2, n)/3 ).at n=10A244469