I took the index of the words, converted the range to binary, additional 3 zeros, calculated the sha256 digest, took the 1st Portion of the hexadecimal to convert it to binary, extra 3 zeros to your eight digits with the binary and bought 00000010011 which interprets to 19 in decimal. https://my-social-box.com/story4321024/how-much-you-need-to-expect-you-ll-pay-for-a-good-bip39-seed-phrase-mnemonics-generator