I took the index with the words, transformed the variety to binary, additional a few zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to transform it to binary, extra three zeros into the 8 digits with the binary and obtained 00000010011 which interprets to 19 in https://bookmarklinking.com/story5605144/how-much-you-need-to-expect-you-ll-pay-for-a-good-valid-bip39-seed-phrase