how many bitcoin address with prefix calcul

[Kostelooscoin]

hello guys,

how many bitcoin address with prefix 12c6

example         12c6                 FtDFVfovY2cxDLDKYghtpa9v                        G1KKeu
            (bitcoin prefix)                     (24^58 ?)                                  (bitcoin checksum)

[BrewMaster]

somewhere between 1 and 31^58 (31 because the longest bitcoin address in base58 can be 35 characters and you fixed the first 4 characters).
if you also fix the checksum which is i believe a little less than 5 characters then the number shrinks by a lot but still can be more than just one since it is a 4 byte collision with only a couple of initial bytes of the data set.

any particular reason you are asking this?

[Kostelooscoin]

somewhere between 1 and 31^58 (31 because the longest bitcoin address in base58 can be 35 characters and you fixed the first 4 characters).
if you also fix the checksum which is i believe a little less than 5 characters then the number shrinks by a lot but still can be more than just one since it is a 4 byte collision with only a couple of initial bytes of the data set.

any particular reason you are asking this?

to understand more and by chance this checksum is calculated?

thanks for response.

[BrewMaster]

to understand more and by chance this checksum is calculated?

then you have to look into how this type of addresses are created (https://en.bitcoin.it/wiki/Technical_background_of_Bitcoin_addresses) and also the encoding used in them (https://en.bitcoin.it/wiki/Base58Check_encoding). going in reverse won't answer your questions.
in short the checksum is calculated by taking the 21 bytes input (version + result of HASH160) and performing 2 times SHA256 on it then taking the first 4 bytes.

[odolvlobo]

The same question was recently asked in this thread: https://bitcointalk.org/index.php?topic=5215344.0

I think it will provide the information you might be looking for.

[bigvito19]

Based off Vanitygen:

The number of all BTC addresses starting with a prefix indicated is:

2^160 / (difficulty of that vanity address).

Then you need a software to compute the difficulty.

12c6  --> difficulty = 77178 -->  number of all BTC addresses starting

12c6 --> 2^160  /  77178 =

18,936,764,846,600,105,188,054,689,584,030,203,162,247,435 that begins with 12c6