{{alias}}( n )
    Computes the nth Lucas number.

    Lucas numbers follow the recurrence relation

      L_n = L_{n-1} + L_{n-2}

    with seed values L_0 = 2 and L_1 = 1.

    If `n` is greater than `76`, the function returns `NaN`, as larger Lucas
    numbers cannot be accurately represented due to limitations of double-
    precision floating-point format.

    If not provided a nonnegative integer value, the function returns `NaN`.

    If provided `NaN`, the function returns `NaN`.

    Parameters
    ----------
    n: integer
        Input value.

    Returns
    -------
    y: integer
        Lucas number.

    Examples
    --------
    > var y = {{alias}}( 0 )
    2
    > y = {{alias}}( 1 )
    1
    > y = {{alias}}( 2 )
    3
    > y = {{alias}}( 3 )
    4
    > y = {{alias}}( 4 )
    7
    > y = {{alias}}( 77 )
    NaN
    > y = {{alias}}( NaN )
    NaN

    See Also
    --------