take-nth

(take-nth n coll) / (take-nth n)

Answers every nth member of coll's seq from the first: a lazy input answers a lazy seq, a strict one a strict list. (take-nth n) is its transducer. As a value one or two arguments.

Deviation: a zero n signals and the seq arity steps by the magnitude of a negative one, where the oracle's seq arity repeats the first member forever.