I took the index of your words, converted the quantity to binary, included 3 zeros, calculated the sha256 digest, took the 1st Portion of the hexadecimal to transform it to binary, added 3 zeros into the eight digits from the binary and obtained 00000010011 which translates to 19 in decimal. https://companyspage.com/story4051008/not-known-factual-statements-about-bip39-explained