I took the index with the words, converted the variety to binary, added 3 zeros, calculated the sha256 digest, took the first Section of the hexadecimal to convert it to binary, additional three zeros to your 8 digits of your binary and received 00000010011 which translates to 19 in decimal. https://bookmarkbooth.com/story19045782/how-much-you-need-to-expect-you-ll-pay-for-a-good-bip39-seed-phrase-mnemonics-generator