This puzzle is very strange. If it's for measuring the world's brute forcing capacity, 161-256 are just a waste (RIPEMD160 entropy is filled by 160, and by all of P2PKH Bitcoin). The puzzle creator could improve the puzzle's utility without bringing in any extra funds from outside - just spend 161-256 across to the unsolved portion 51-160, and roughly treble the puzzle's content density.
If on the other hand there's a pattern to find... well... that's awfully open-ended... can we have a hint or two?

I am the creator.
help me buy my children a new piano to learn. the old piano is broken and the new one is expensive. I also need to pay for my children's tuition at a music school! dear Satoshi nakomoto, if you help, my children will remember you all their lives! take at least one useful good step in your life! the whole bitcointalk will kiss you and respect you! the whole bitcoin talk is watching this address and if it is replenished, then great respect from the whole community will be for you! 1onuEA5qCoV2SfwUUYRSGiN4ZReaH4BrH