Share good ideas and conversation.   Login, Join Us, or Take a Tour!
mike  ·  1186 days ago  ·  link  ·    ·  parent  ·  post: Fun and hard little math puzzle

I like your double exclamation point at the end of your comment!!

I'll argue it's not harder to use in solutions -- I gave an explanation in the puzzle to open up the possibility, and it's a pretty short list of operands that are useful:

4!! = 8

5!! = 15

6!! = 48

7!! = 105

after that, the numbers get too big to be useful. I didn't find a use for 5!! or 7!!, but certainly there are more solutions I haven't found!