I took the index of your words, converted the variety to binary, added a few zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to transform it to binary, extra three zeros for the eight digits from the binary and obtained 00000010011 which translates to 19 in https://nybookmark.com/story20438633/the-ultimate-guide-to-bip39-seed-phrase-github