I took the index of the words, transformed the amount to binary, extra 3 zeros, calculated the sha256 digest, took the initial Component of the hexadecimal to transform it to binary, included 3 zeros to your 8 digits in the binary and obtained 00000010011 which interprets to 19 in decimal. https://nimmansocial.com/story8647840/an-unbiased-view-of-bip39-seed-phrase-github