I took the index of your words, converted the variety to binary, included 3 zeros, calculated the sha256 digest, took the main Portion of the hexadecimal to transform it to binary, included 3 zeros to your 8 digits in the binary and obtained 00000010011 which translates to 19 in decimal. https://writeablog.net/ipennywpzc/h1-b-opening-the-power-of-bip39-exactly-how-to-produce-and-use-mnemonic