4 ms·
Keep in mind, though, that you would want to write it (9!)! or ((9!)!)!. 9!! is actually the double factorial, which is defined as 9!! = 1 * 3 * 5 * 7 * 9. So
by splat 14y ago
Keep in mind, though, that you would want to write it (9!)! or ((9!)!)!. 9!! is actually the double factorial, which is defined as 9!! = 1 * 3 * 5 * 7 * 9. So 9!! < 9!.
- jrockway 14y agoI've never heard of that, but sure, do (9!)!. Since the problem as stated by the OP (not the article itself) specifies that only 9s are limited, it doesn't make a difference.