Re: Generate an address with certain letters

I can't do it precisely if I remove letters from the base58 bitcoin addresses are invalid

If you meant Bitcoin address with shorter length (shorter than 26), then it's impossible.

See https://en.bitcoin.it/wiki/Address#What.27s_in_an_address

Quote

ex: 15nE3ebnYkJYRok2H9H9Xdw1widwPtYt7TD4
1E3en5widwbn..........
1onbwE53................

You're going to have to limit the prefix length, or it will take forever to create. Also, lower case "o" isn't allowed.

According to https://en.bitcoin.it/wiki/Base58Check_encoding#Base58_symbol_chart, lower case "o" is allowed, characters which aren't allowed are 0 (zero), O (upper case "o"), I (upper case "i"), and l (lower case "L")