I took the index of your words, transformed the range to binary, additional three zeros, calculated the sha256 digest, took the primary Component 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://hypebookmarking.com/story18690039/bip39-seed-phrase-fundamentals-explained