294293759760domain: NAppears in sequencesa(n) = 7^n - 6*6^n + 15*5^n - 20*4^n + 15*3^n - 6*2^n + 1.at n=14A228909G.f.: Sum_{n>=0} n^(2*n) * x^n / (1 + n^2*x)^n.at n=7A243227