(adsbygoogle = window.adsbygoogle || []).push({}); [SOLVED] Onto, but not one-to-one

I need a function

f: N -> N such that f is onto, but not one-to-one, and I can't think of one to save my life, any suggestions?

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# Onto, but not one-to-one

**Physics Forums | Science Articles, Homework Help, Discussion**