I took the index with the words, transformed the variety to binary, extra 3 zeros, calculated the sha256 digest, took the main part of the hexadecimal to convert it to binary, included three zeros on the 8 digits on the binary and obtained 00000010011 which translates to 19 in decimal. https://extrabookmarking.com/story18839397/the-invalid-bip39-phrase-diaries