I took the index from the words, transformed the selection to binary, additional 3 zeros, calculated the sha256 digest, took the main Portion of the hexadecimal to transform it to binary, additional a few zeros towards the 8 digits on the binary and got 00000010011 which interprets to 19 in https://fellowfavorite.com/story20213044/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting