I took the index of your words, transformed the quantity to binary, extra 3 zeros, calculated the sha256 digest, took the first part of the hexadecimal to transform it to binary, added 3 zeros to your 8 digits of your binary and received 00000010011 which interprets to 19 in decimal. https://dftsocial.com/story19826545/fascination-about-bip39-english-words