4280561376domain: NAppears in sequencesa(n) = binomial coefficient C(2n, n-10).at n=11A004316Binomial coefficient C(3n, n-3).at n=11A004321Binomial coefficient C(42,n).at n=11A010958Binomial coefficient C(n,31).at n=11A010984a(n) = binomial(sigma(n+1), sigma(n)).at n=24A078504