1636944domain: NAppears in sequencesa(n) = Sum_{k=0..n} binomial(5*k,n-k).at n=12A360090Number of compositions of 6*n into parts 1 and 6.at n=10A371125a(n) = Sum_{k=0..floor(n/2)} binomial(3*n-5*k,k).at n=20A373638a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-5*k,k).at n=30A373639