Question 252353
Lset S = (1*2*3)+(2*3*4)+(3*4*5)+.....................100 terms
The nth term Tn = n*(n+1)*(n+2)
                = n*(n^2+2n+n+2)
                = n*(n^2+3n+2)
                = n^3+3n^2+2n
Sum to n terms  = sum( n^3 +3n^2+2n, i=1, n )
                = n^2(n+1)^2 /4 + 3 n(n+1)(2n+1)/6 + 2n(n+1)/2
Put n = 100
Sum to 100 terms = (100)^2(101)^2 /4 +3x100x(101)x(201)/6 +100(101)
                 = 25502500+1015050+10100
                 = 26527650