Is there a BTC Address generator that will check first blockchain if unused? I'm looking for a working implementation of a Bitcoin address generator that would accept string or integer then it will check the blockchain if the address is unused before it will print the keypairs.

Any repositories with similar function is highly appreciated.
Thank you.
No wallet software checks to see if they are 'used'- for you to have a collision in addresses would be astronomically unlikely (impossible for this sort of scenario), or indicative that you're not safely creating entropy for your keys.