I took the index with the words, transformed the variety to binary, extra 3 zeros, calculated the sha256 digest, took the main A part of the hexadecimal to transform it to binary, extra 3 zeros towards the 8 digits with the binary and got 00000010011 which translates to 19 in https://bookmarkmargin.com/story18954665/fascination-about-invalid-bip39-phrase