I took the index in the words, converted the selection to binary, added 3 zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to transform it to binary, extra a few zeros towards the 8 digits from the binary and got 00000010011 which interprets to 19 in https://getsocialselling.com/story4209584/an-unbiased-view-of-bip39-seed-phrase-github