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Contents
describe Integer, "#dihedral_prime?" do
# http://www.research.att.com/~njas/sequences/A038136
DIHEDRAL_PRIME = ([2,11,101,181,1181,1811,18181,108881,110881,
118081,120121,121021,121151,150151,151051,151121,
180181,180811,181081,188011,188801,1008001,
1022201,1028011,1055501,1058011,1082801,1085801,
1088081] +
# http://www.research.att.com/~njas/sequences/A134996
[2,5,11,101,181,1181,1811,18181,108881,110881,
118081,120121,121021,121151,150151,151051,151121,
180181,180811,181081,188011,188801,1008001,
1022201,1028011,1055501,1058011,1082801,1085801,
1088081]).uniq
it "returns true for Dihedral primes" do
DIHEDRAL_PRIME.each do |number|
number.should be_dihedral_prime
end
end
it "returns false for non-Dihedral primes" do
[6,12,4827290].each do |number|
number.should_not be_dihedral_prime
end
end
it "returns false for primes which aren't Dihedral" do
[3,17,19].each do |number|
number.should_not be_dihedral_prime
end
end
it "returns false for non-primes which are Dihedral" do
[8, 808, 1101].each do |number|
number.should_not be_dihedral_prime
end
end
end
Version data entries
16 entries across 16 versions & 1 rubygems