How to quickly solve a to the nth power times a to the nth power minus 1 times a to the nth power minus 2, etc. for a = 2 and n= 3
Is this what you mean ?
an∗a(n−1)∗a(n−2)......∗an−n=23∗2(3−1)∗2(3−2)∗2(3−3)=23∗22∗21∗20=8∗4∗2∗1=64