I have a line like this:

The values are not perfect (means the values can be changed), but all are non-negative values. I like to know the equation's equation or function.
I have tried-
$y=\ln(x)$
$y=e^x$
$y=\sin(x)$
$y=\tan(x)$
But nothing is matching this equation so much. I am thinking it may be some kind of transformations of $y=1/e^x$, but I am not sure about it.
So, can anyone please help me to find the equation formula, please?
Thanks in advance for helping :)
I have solved it like this-
$$f(x) = ab^{x}$$
Where: $$ a > 0 $$ $$ 0< b < 1 $$ $$ x\ge 0 , x \in Z $$
More can be found in here.