Anonymous function returning 1 using #()

#(do %& 1) ... but (constantly 1) is better.

The #() syntax can't be used to create functions that have unused parameters in the way your description requires. This is a limitation of the #() reader macro.

I would recommend not using #() and instead just writing (constantly 1) which is a very brief way to create a function that ignores a parameter and instead always returns 1.