I took the index in the words, converted the quantity to binary, additional 3 zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to convert it to binary, extra a few zeros to the 8 digits in the binary and obtained 00000010011 which interprets to 19 in https://bookmarkchamp.com/story18847463/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting