I took the index with the words, converted the variety to binary, included 3 zeros, calculated the sha256 digest, took the 1st Portion of the hexadecimal to convert it to binary, extra 3 zeros on the eight digits on the binary and got 00000010011 which translates to 19 in decimal. https://bookmarklogin.com/story19730911/how-much-you-need-to-expect-you-ll-pay-for-a-good-valid-bip39-seed-phrase