I took the index with the words, transformed the range to binary, extra a few zeros, calculated the sha256 digest, took the main Element of the hexadecimal to transform it to binary, included a few zeros on the 8 digits in the binary and obtained 00000010011 which translates to 19 https://onlybookmarkings.com/story18750204/ledger-seed-phrase-bip39-no-further-a-mystery