#NewStack, 14 bytes
NewStack, 14 bytes
N∞ ḟᵢfi 'fif Ṗf⁻
The breakdown:
N∞ Add all natural numbers to the stack
ḟᵢ Define new function will value of input
fi Get the n'th Fibonacci number for ever element n
'fif Remove all elements that don't contain the (input)'th Fibonacci number
Ṗf⁻ Print the (input-1)'th element
In English: (with example of an input of 3)
N∞
: Make a list of the natural numbers [1,2,3,4,5,6...]
ḟᵢ
: Store the input in the variable f
[1,2,3,4,5,6...]
fi
: Convert the list to Fibonacci numbers [1,1,2,3,5,8...]
'fif
: Keep all elements that contain the f
th Fibonacci number [2,21,233...]
Ṗf⁻
: Print the f-1
th element (-1 due to 0-based indexing) 233