Problem Statement

The   population count   is the number of   1s   (ones)   in the binary representation of a non-negative integer. Population count   is also known as:

For example,   5   (which is   101   in binary)   has a population count of   2.

Evil numbers   are non-negative integers that have an   even   population count. Odious numbers     are  positive integers that have an    odd   population count.

Let's start with the solution:

popCount: function [num][
    size select split to :string as.binary num 'x -> x="1"
]

print "population count for the first thirty powers of 3:"
print map 0..29 => [popCount 3^&]

print "first thirty evil numbers"
print take select 0..100 => [even? popCount &] 30

print "first thirty odious numbers"
print take select 0..100 => [odd? popCount &] 30