Number sequences

Question 1

Number of dots for nth diagrams, Dn, Sum of number of dots for the first n diagrams, Sn
1: 3, 3
2: 7, 10
3: 11, 21
4: 15, 36
Find row 5 and the equations for Dn and Sn

Answer 1

5: 19, 55
Dn= 4n-1
Sn= n(2n+1)