can you help me in this question

[closed account 1TD80pDG]

,

[closed account 1TD80pDG]

anyone please help me ?

[closed account 3UohqMoL]

@ipg can you help me with this

i think it is Geometric Progression.
Can you help to optimize it ?

https://www.codechef.com/ISCC2018/problems/T24