Contents

describe Integer, "#decagonal?" do
  # A001107
  DECAGONAL = [0,1,10,27,52,85,126,175,232,297,370,451,540,637,
               742,855,976,1105,1242,1387,1540,1701,1870,2047,
               2232,2425,2626,2835,3052,3277,3510,3751,4000,4257,
               4522,4795,5076,5365,5662,5967,6280,6601,6930,7267,
               7612,7965,8326]

  it "returns true for a decagonal number" do
    DECAGONAL.each{|n| n.should be_decagonal}
  end

  it "returns false for a non-decagonal number" do
    ((0..DECAGONAL.last).to_a - DECAGONAL).each{|n| n.should_not be_decagonal}
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
numb-0.21.0	spec/decagonal_spec.rb
numb-0.20.0	spec/decagonal_spec.rb