Re: [Haskell-cafe] List of all powers

On Wed, 14 Nov 2007, Kurt Hutchinson wrote:

As part of a solution I'm working on for Project Euler problem 119, I wanted to create an ordered list of all powers of all positive integers (starting with squares). This is what I came up with:

powers = ( uniq . map fst . iterate next ) ( 1, ( 0, powertable ) )

powertable = map (\ n -> map (\ p -> n ^ p ) [ 2 .. ] ) [ 2 .. ]

iterate (n*) (n^2) should be much more efficient.