Sha256: cbe5e9e68ce72c630916c78f9042ac9af81dd4bf4649c721831ce50e7f795181
Contents?: true
Size: 444 Bytes
Versions: 27
Compression:
Stored size: 444 Bytes
Contents
# coding: utf-8
class Integer
# An emrip is a prime whose reversed digits give a different prime. For
# example, 17 is an emrip because 71 is also prime.
#
# Returns true if self is an emrip; false otherwise.
#
# 1009.emrip? #=> true
# 1193.emrip? #=> true
# 7.emrip? #=> false
#
def emrip?
return false unless prime?
reversed = to_s.reverse.to_i
reversed != self and reversed.prime?
end
end
Version data entries
27 entries across 27 versions & 1 rubygems