I took the index in the words, converted the amount to binary, included 3 zeros, calculated the sha256 digest, took the first part of the hexadecimal to transform it to binary, additional a few zeros to the 8 digits on the binary and got 00000010011 which translates to 19 in https://geniusbookmarks.com/story19462606/a-review-of-bip39-passphrase