The series is 18 +1² = 19; 19 + 2² = 23; 23 + 3² = 32;
32 + 4² = 48; 48 + 5² = 73 + 6² = 109

The series is x 2 + 1, x 2 + 2, x 2 + 3, x 2 + 4, x 2 + 5

(2 - 1) x 7 = 7; (7 - 2) x 6 = 30; (30 - 3) x 5 = 135; (135 - 4) x 4 = 524;
(524 - 5) x 3 = 1557; (1557 - 6) x 2 = 3102

The series is x 2 - 2, x 2 - 2, x 2 - 2, x 2 - 2, ......

Pattern is x 2 + 1, x 3 + 1, x 2 + 1, x 3 + 1, ........

Pattern is : x 1 + 1, x 2 + 2, x 3 + 3, x 4 + 4, ............

Pattern is : - 192, - 96, - 48, - 24, -12, - 6

Pattern is : + 6, + 12, + 24, + 48, +96, + 192

Pattern is : the series is the combination of three series -each term is twice the preceding term.
(i) 1^st, 4^st, 7^st term i. e 2,4,9,.......
(ii) 2^st, 5^st, 8^st term i, e 3,6,12.....
(iii) 3^st, 6^st, 9^st 4,8,16......
So, 9 is wrong.

4 x 4 + (4 x 3) = 28
28 x 5 + (5 x 4) =160
160 x 6 + (6 x 5) = 990
990 x 7 + (7 x 6) = 6972
6972 x 8 + (8 x 7) = 55832
55832 x 9 + (9 x 8) = 502560