Let M be the 3 X 3 matrix [0 1 0 / 0 0 1 / 7 -35 21]. Take M^n * [1 1 1] = [p q r]; then a(n-1), a(n), a(n+1) = -p, -q, -r respectively.

A094257

Let M be the 3 X 3 matrix [0 1 0 / 0 0 1 / 7 -35 21]. Take M^n * [1 1 1] = [p q r]; then a(n-1), a(n), a(n+1) = -p, -q, -r respectively.