Step 0 ---- 2
2+1
step 1 ------ 3
3+3
step 2 --------- 6
6+5
step 3 ----------11
11 + 7
step 4 ------------ 18
terms are 2, 3, 6,11, 18
There is an increment of odd numbers from a preceding term
2 increase to 3 by the first odd i.e 1
3 increase to 6 by the next odd i.e 3
6 increase to 11 by the next odd i.e 5
Therefore 11 will increase by the next odd, i.e 7
Thus, 11 + 7 = 18