Features:
The large square is 17x17 and has a magic sum of 1105 for all horizontals, verticals, and the two diagonals. Its numbers run consecutively from a negative 47 through zero to 177.
The number 65 appears 65 times.
Sixty-four of these are used to segregate the nine component 5x5 squares, each with its own magic sum
(-175, -50, +75, +200, +325, +450, +575, +700, +825),
while one appears as part of the center square.