I took the index of your words, converted the quantity to binary, extra three zeros, calculated the sha256 digest, took the primary Section of the hexadecimal to transform it to binary, included 3 zeros for the eight digits with the binary and received 00000010011 which interprets to 19 in decimal. https://mediajx.com/story21551949/the-basic-principles-of-bip39-passphrase-generator