Un = n² (n + 1)U₁ = 1² (1 + 1) = 1 · 2 = 2U₂ = 2² (2 + 1) = 4 · 3 = 12U₃ = 3² (3 + 1) = 9 · 4 = 362, 12, 36, 80, 150, ...
cek grafiknya