How did i write this formula 2*n-1 in recursive function?

Answer 1

func(int n) {
If(n==0) return 1;
return 2*func(n-1);
} //Something like this

Answer 2

I using this method when i enter 2 , output not 3

Answer 3

You are asking for power right?

2 (raised to the power) n-1

Answer 4

My question is like this
1,3,7,15,31,63
when i enter 6 it will display 63