Answer:
an= n * (n+1)
Step-by-step explanation:
2,6,12,20,.....
6-2 =4
12-6 = 6
So there is no common difference because these numbers are not the same
It cannot be an arithmetic difference
6/2 =3
12/6 =2
So there is no common ratio because these numbers are not the same
It cannot be geometric
2, 6, 12, 20,...
+4 +6 +8 +10
a1 =2
a2 =2*3
a3 = 2*6=2*2*3=3*4
a4=2*10=2*2*5=4*5
.....
a5 = 5*6 = 30
an= n * (n+1)
