I took the index of your words, converted the amount to binary, extra a few zeros, calculated the sha256 digest, took the main Element of the hexadecimal to transform it to binary, included three zeros to the 8 digits from the binary and got 00000010011 which translates to 19 in https://bookmark-group.com/story4365985/little-known-facts-about-bip39-seed-phrase-list