Find the rule: 2, 5, 11, 20, (), ()

Find the rule: 2, 5, 11, 20, (), ()


32, 47. From the previous number + 3, + 6, + 9, + 12, + 15



5,4,2, - 1 () () - 2, - 5, - 11, - 23 () ()


5,4,2,-1 ( -5) ( -10)
-2,-5,-11,-23( -47) ( -95)



Find the rule: - 1,2. - 5.10. - 17
-1,2, - 5,10, - 17, (), (), (), () to 2009


General term formula = (- 1) nth power ((n-1) power + 1)
So the next one is 26, - 37
The 2009 one is - 4032065