I took the index on the words, converted the variety to binary, added three zeros, calculated the sha256 digest, took the primary part of the hexadecimal to convert it to binary, added 3 zeros to your eight digits on the binary and bought 00000010011 which translates to 19 in decimal. https://socialicus.com/story4912906/a-secret-weapon-for-bip39-words-to-numbers