Question 884848
This is a quadratic sequence of order 2
4  10  18  28  40
  6   8  10  12
    2  2   2
for nth term we know we have a n^2 term
     4  10  18  28  40
nth  1   2   3   4   5
n^2  1   4   9  16  25
     3   6   9  12  15
therefore the nth term is
nth = n^2 +3n