Nth term of a series

can any1 tell me the nth term of the given sequence…


a[n] = n! + 2^n - n

Where a is an array of numbers and n is the index of the number.
And the indexes start from 1.


what method did you use to find out that ?

Most of what I did wasn’t very legit. Just intuition and graphing.

Judging from the huge increase in numbers, it was either a high exponential or a factorial. I, luckily, stuck with factorial.

After subtracting the factorial sequence, I got the sequence 1, 2, 5, 12, 27, 58. I plugged this into my calculator with, and got a graph incredibly similar to 2^n, then I subtracted 2^n and got 1, 2, 3, 4, 5, 6.

Sorry if you were looking for a complete algebraic solution.