I took the index on the words, converted the variety to binary, extra 3 zeros, calculated the sha256 digest, took the main Section of the hexadecimal to convert it to binary, added 3 zeros for the 8 digits in the binary and got 00000010011 which translates to 19 in decimal. https://thegreatbookmark.com/story18864191/invalid-bip39-phrase-things-to-know-before-you-buy