Sha256: ff544483ac9edbff8306b67187bc0463153f64275dcc3b3b40e697eb3dc985ec
Contents?: true
Size: 1.02 KB
Versions: 15
Compression:
Stored size: 1.02 KB
Contents
describe Integer, "#twin_prime?" do
# A001359, A006512
@seq = [3,5,11,17,29,41,59,71,101,107,137,149,179,191,
197,227,239,269,281,311,347,419,431,461,521,569,
599,617,641,659,809,821,827,857,881,1019,1031,
1049,1061,1091,1151,1229,1277,1289,1301,1319,1427,
1451,1481,1487,1607].zip(
[5,7,13,19,31,43,61,73,103,109,139,151,181,193,
199,229,241,271,283,313,349,421,433,463,523,571,
601,619,643,661,811,823,829,859,883,1021,1033,
1051,1063,1093,1153,1231,1279,1291,1303,1321,1429,
1453,1483,1489,1609])
@seq.each do |p, q|
it "should return true for twin-primes #{p} and #{q}" do
p.twin_prime?(q).should be_true
end
end
it "returns false for two primes which are not twin" do
2.twin_prime?(29).should be_false
end
it "returns false for a prime and a composite" do
17.twin_prime?(20).should be_false
end
it "returns false for two composites with a difference of two" do
20.twin_prime?(22).should be_false
end
end
Version data entries
15 entries across 15 versions & 1 rubygems