Induction!
The years Y = 1, 9, 36, 100, 225, 441, 784, 1296, 2025, 3025 … all follow the pattern Y = square of (1 + … + n) = 1 cubed + … + n cubed.
The years Y = 1, 9, 36, 100, 225, 441, 784, 1296, 2025, 3025 … all follow the pattern Y = square of (1 + … + n) = 1 cubed + … + n cubed.