I took the index with the words, converted the amount to binary, extra 3 zeros, calculated the sha256 digest, took the main part of the hexadecimal to convert it to binary, extra 3 zeros for the 8 digits on the binary and got 00000010011 which translates to 19 in decimal. https://sites2000.com/story8451717/invalid-bip39-phrase-things-to-know-before-you-buy