I took the index in the words, converted the amount to binary, added a few zeros, calculated the sha256 digest, took the main A part of the hexadecimal to transform it to binary, additional three zeros to your eight digits in the binary and obtained 00000010011 which interprets to 19 https://one-bookmark.com/story19412173/ledger-seed-phrase-bip39-no-further-a-mystery