I took the index of the words, transformed the amount to binary, extra a few zeros, calculated the sha256 digest, took the first Element of the hexadecimal to transform it to binary, included three zeros into the 8 digits on the binary and received 00000010011 which translates to 19 in https://networkbookmarks.com/story18822041/5-simple-techniques-for-bip39-word-list-pdf