I took the index from the words, converted the variety to binary, added three zeros, calculated the sha256 digest, took the initial A part of the hexadecimal to convert it to binary, extra 3 zeros on the 8 digits in the binary and obtained 00000010011 which interprets to 19 in https://modernbookmarks.com/story18704470/a-secret-weapon-for-bip39-words-to-numbers