The series seems to be "add 3," so the next number in the series would be 12 followed by 15.
11 comes next.
20
10
144, 288, 576, 1152, e.c.t...
3 * 2 = 6 * 3= 18 *4 =72 *5 = 360
10,11,13,14,15,17
27
The number that comes next in the series 1 2 2 5 3 10 is 7. You get this number by subtracting the number 3 from the number 10.
6; alternating decreasing series, by twos
The series goes like this 2 = 1^2 + 1^3 (1 square + 1 cube) 12 = 2^2 + 2^3 36 = 3^2 + 3^3 and so on.. So, the next number in the series is 6^2 + 6^3 = 252.
1, 2, 0, 3, -1, 4, -2, 5, -3, 6
7 then 7 then 5 then 6