I took the index with the words, converted the variety to binary, added 3 zeros, calculated the sha256 digest, took the first Component of the hexadecimal to transform it to binary, included three zeros towards the eight digits in the binary and got 00000010011 which interprets to 19 in decimal. https://bookmarktiger.com/story18791699/considerations-to-know-about-bip39-word-list-pdf