Another approach for D, There was a pattern hidden in it. first number = (1<<n)-1, hence the adder here is (1<<(n+2)), add this number and insert this into the answer array this it reaches or exceeds (1<<n). Next number = (1<<n-1)-1, repeat the process. Stop when the answer array size is (1<<n). 354825334

Congrats Dominator069, you deserve it