Contents

# coding: utf-8
class Integer
  def nsw
    case self
      when 0 then 1
      when 1 then 7
      else        6 * (self - 1).nsw - (self - 2).nsw
    end
  end
  memoize(:nsw)
  
  def nsw?
    m = self
    (rhs = (m**2).succ).divides?(2) and 2 * ((rhs/2).isqrt**2) == rhs
  end
end

Version data entries

6 entries across 6 versions & 1 rubygems

Version	Path
numb-0.186.0	lib/numb/nsw.rb
numb-0.185.0	lib/numb/nsw.rb
numb-0.184.0	lib/numb/nsw.rb
numb-0.181.0	lib/numb/nsw.rb
numb-0.170.0	lib/numb/nsw.rb
numb-0.152.0	lib/numb/nsw.rb