180216domain: NAppears in sequencesa(n) = Sum_{k = 0..n } binomial(n + 1, k + 1)*binomial(n, k)*k!.at n=7A129833Number of 1:3:sqrt(10) proportioned triangles on a (n+1) X (n+1) grid.at n=30A190102Numbers k such that Bernoulli number B_{k} has denominator 140100870.at n=28A295599