I took the index of your words, transformed the quantity to binary, added 3 zeros, calculated the sha256 digest, took the primary part of the hexadecimal to convert it to binary, additional 3 zeros to your 8 digits of the binary and obtained 00000010011 which interprets to 19 in decimal. https://free-bookmarking.com/story18934745/the-5-second-trick-for-ledger-seed-phrase-bip39