(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?

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

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Onto, but not one-to-one

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