I took the index with the words, transformed the range to binary, extra 3 zeros, calculated the sha256 digest, took the 1st part of the hexadecimal to convert it to binary, added a few zeros to the 8 digits of the binary and got 00000010011 which translates to 19 in http://rylanmecp341.wpsuo.com/from-words-to-wide-range-exactly-how-to-efficiently-make-use-of-bip39-passphrases-for-your-copyright-pocketbooks