I took the index of your words, transformed the amount to binary, included three zeros, calculated the sha256 digest, took the first A part of the hexadecimal to convert it to binary, added three zeros towards the 8 digits from the binary and got 00000010011 which interprets to 19 in https://keybookmarks.com/story19641304/an-unbiased-view-of-bip39-seed-phrase-github