I took the index of your words, transformed the quantity to binary, included three zeros, calculated the sha256 digest, took the initial Section of the hexadecimal to convert it to binary, additional three zeros on the 8 digits from the binary and bought 00000010011 which interprets to 19 in decimal. https://socialimarketing.com/story4354011/a-secret-weapon-for-bip39-words-to-numbers