I took the index in the words, transformed the amount to binary, extra a few zeros, calculated the sha256 digest, took the 1st A part of the hexadecimal to transform it to binary, extra three zeros to the 8 digits of your binary and got 00000010011 which interprets to 19 https://alphabookmarking.com/story19034461/a-review-of-bip39-phrase-list