**This forms an arithmetic series with:**

First term =8,002,000

Difference for each term= -(1/2(n^3+n^2) =31,973,323,333/7,998

Number of Terms =4,000

∑[8,002,000*n -(1/2(n^3+n^2)), n, 1, 4000]=32,005,331,333,000

**Or, using AP Formula, we get:**

**4000/2*(8002000*2 + (31973323333/7998*3999))=32,005,331,333,000**