rumus dari 5,7,11,17,25...

Deret Aritmatika Bertingkat
a.......5.....7.....11.....17.....25
b...........2....4.....6......8....
c..............2......2.....2...

• 2A = c
2A = 2
A = 1

• 3A + B = b
3.1 + B = 2
B = -1

• A + B + C = a
1 - 1 + C = 5
C = 5

Un = An² + Bn + C
Un = n² - n + 5