n = 16
50000(1 + 1.04 + 1.04^2 + 1.04^3 + .... + 1.04^15) = 50000 * (1.04^16 - 1) / (1.04 - 1) = 1,091,226.56
Final year's salary = 90047.17
86,583.82 * 1.04 = 90047.17
There are only 15 table when there should be 16.
a_N = 50000(1.04)^15 = 90047.17
And if we add 90047.17 to the previous total of 1001179.38 we get
$1,091,226.55