I took the index of your words, converted the amount to binary, included 3 zeros, calculated the sha256 digest, took the 1st Section of the hexadecimal to transform it to binary, additional 3 zeros on the 8 digits in the binary and acquired 00000010011 which translates to 19 in decimal. https://listfav.com/story21257112/not-known-factual-statements-about-bip39-explained