Step-by-step explanation:
each term in the sequence is half of the value of the previous term, and in the opposite sign.
therfore, the quotient between terms is (-2)
so, to get one term from the previous term, we multiply by 1/(-2), so:
d(n) = d(n-1) × 1/(-2)
the first term is 56 so d(1)=56
