I took the index of your words, converted the number to binary, extra 3 zeros, calculated the sha256 digest, took the main Component of the hexadecimal to transform it to binary, included 3 zeros on the eight digits of the binary and got 00000010011 which translates to 19 in decimal. https://captainbookmark.com/story18860823/top-guidelines-of-bip39-word-list-pdf