I took the index on the words, transformed the range to binary, extra a few zeros, calculated the sha256 digest, took the primary Component of the hexadecimal to transform it to binary, extra 3 zeros to the 8 digits of the binary and got 00000010011 which interprets to 19 in https://bookmarklinkz.com/story18889291/a-secret-weapon-for-bip39-words-to-numbers