I took the index of your words, transformed the variety to binary, included a few zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to transform it to binary, added three zeros towards the 8 digits in the binary and received 00000010011 which translates to 19 in https://trackbookmark.com/story20293790/an-unbiased-view-of-bip39-seed-phrase-github