redundancy vs redundance

redundancy and redundance both are nouns.

Word	Noun	Adjective	Verb	Adverb
redundancy	Yes	No	No	No
redundance	Yes	No	No	No

As nouns, redundancy and redundance are synonyms defined as:

redundancy and redundance: the attribute of being superfluous and unneeded

redundancy (noun)	redundance (noun)
repetition of an act needlessly	the attribute of being superfluous and unneeded
the attribute of being superfluous and unneeded
(electronics) a system design that duplicates components to provide alternatives in case one component fails
repetition of messages to reduce the probability of errors in transmission