488281250000domain: NAppears in sequencesa(n) = Sum_{k=0..n} (k+1) * T(n,k), with T given by A026374.at n=30A026950a(n) = n*5^(n-1).at n=16A053464Expansion of (1-x)^2/(1-5*x).at n=17A055842Denominator of Euler(n, 1/5).at n=15A156183Hypotenuses for which there exist exactly 15 distinct integer triangles.at n=11A290503