Rumus suku ke – n barisan bilangan 1,4,9,16,….

n = 1 —> (1-1)² = 0
n = 2 —> (2-1)² = 1
n = 3 —> (3-1)² = 4
n = 4 —> (4-1)² = 9
n = 5 —> (5-1)² = 16

Semoga bermanfaat ;)