I took the index in the words, transformed the selection to binary, additional 3 zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to transform it to binary, included 3 zeros to your eight digits on the binary and got 00000010011 which interprets to 19 in decimal. https://bookmarkspedia.com/story4342395/the-invalid-bip39-phrase-diaries