I didn't see anyone using this formula yet, so here it is (in Python).

```
def climbStairs(self, n):
return int(((1 + 5**.5) / 2) ** -~n / 5**.5 + .5)
```

(No, I would not be able to recall that formula in an interview. There I would do my normal solution or maybe the matrix solution, which is not that hard to remember)

If you're wondering about `-~n`

, that's just short for `(n+1)`

. Apparently I was in golfing mode.