Return double factorial
n(n-2)...(5)(3)(1), n>0, odd n!! = n(n-2)...(6)(4)(2), n>0, even 1 , n = -1, or n = 0
For example
6!! = (6)(4)(2) = 48
Neither n = -1, nor n = 0 are tested.
Back to basics 25 - Valid variable names
253 Solvers
316 Solvers
328 Solvers
64 Solvers
Optimization of cylinder surface area
17 Solvers