come up with vs get on to

come up with

verb
  • Used other than figuratively or idiomatically: see come, up, with. 

  • To reach or overtake. 

  • To manage to produce, deliver, or present (something) by inventing, creating, thinking of, or obtaining it. 

get on to

verb
  • Used other than figuratively or idiomatically: see get on, to. 

  • To contact (someone) in order to raise or discuss a certain matter. 

  • To progress to; to start working on. 

How often have the words come up with and get on to occurred in a corpus of books? (source: Google Ngram Viewer )