I took the index with the words, transformed the amount to binary, extra 3 zeros, calculated the sha256 digest, took the main part of the hexadecimal to convert it to binary, additional three zeros on the eight digits on the binary and received 00000010011 which translates to 19 in decimal. https://thegreatbookmark.com/story18850023/a-secret-weapon-for-bip39-words-to-numbers