What would it do if multiple addresses share those bits?

icebraining · on June 13, 2014

  Any time a Bitcoin address is used for transactional purposes and appears in the
  block chain, its firstbits - or the prefix that uniquely identifies that address
  within the block chain - are considered assigned at that time. If another address
  is created and used with the same prefix at a later time, the firstbits of that
  new address will be at least one character longer, as the shorter prefix remains
  reserved for the address that used it first.

https://en.bitcoin.it/wiki/Firstbits

benmanns · on June 13, 2014

Ah, that's pretty cool. Otherwise you can use things like vanitygen to create a similar address. I just created https://duckduckgo.com/?q=1NhLgwwuiyVsBuk3NgJHDztZZ6ejBySbsj