I'm looking for a word that describes things which are not consecutive, but are separated by one item.
For example, 1,2,3,4 are consecutive numbers. 2,4,6,8 are ______ numbers.
This is actually for a math question. I see questions asking about "consecutive even numbers" or "consecutive odd numbers", but how would one, in a similar manner, describe the general case of integers with a difference of two.
I'm hoping for a general word, which could also be applied as, for example:
Sunday, Tuesday, Thursday, Saturday is a series of _______ days.