I took the index of your words, transformed the selection to binary, additional three zeros, calculated the sha256 digest, took the main Element of the hexadecimal to convert it to binary, added 3 zeros into the 8 digits with the binary and received 00000010011 which translates to 19 in decimal. https://exactlybookmarks.com/story19426777/5-simple-techniques-for-bip39-word-list-pdf