-2828

Appears in sequences

• a(n) = -(n + 1)*(2*n^2 + n - 12)/6.at n=20A058372
• Triangle T(n,k) read by rows: coefficient of [x^k] of the polynomial p_n(x)=(5-x)*p_{n-1}(x)-p_{n-2}(x), p_0=1, p_1=5-x.at n=16A179900