I took the index of your words, transformed the quantity to binary, additional 3 zeros, calculated the sha256 digest, took the main Section of the hexadecimal to transform it to binary, included 3 zeros into the 8 digits with the binary and received 00000010011 which interprets to 19 in decimal. https://socialbuzzfeed.com/story4509723/detailed-notes-on-copyright-wallet-seed-phrase-out-of-bip39