The Fibonacci Calculator requires Javascript (which is NOT the same as Java).
JavaScript can be used in:
• Internet Explorer, version 4 or later;
• Netscape Navigator, version 4 or later. Make sure Navigator (or Communicator) has Javascript enabled in your Preferences:
in Edit, Preferences, Advanced, check the box marked Javascript.
Fibonacci and Lucas Number Calculator 1.2     For help, see lower down.
Series? Value or Range for i? Action buttons
 Fibonacci(i) Lucas(i) Approximate(faster) Exact(slower)
 From i= To i=

Rabbit(i)
Eval:
The calculator is     <<< ready for you     <<< computing - please wait...

### HOW TO USE THIS CALCULATOR

[Links followed will open in a new window.]
1. Select a series:
Fibonacci(i), Lucas(i), Rabbit(i).
For Fibonacci(i) and Lucas(i) you have a choice of Precision: exact or approximate.
Exact: the calculator will find Fibonacci(i) and Lucas(i) for i into the thousands. However, if i is too large, the browser may quit unexpectedly! (Sorry - I cannot predict or prevent this! 'i' values up to i=2000 (Fib(2000) has 400+ digits) should be OK.
Approximate: Immediate result. The length of the answer decreases as i gets larger, but the index i itself may have up to digits!

The Eval box lets you input an expression which uses i. Details below.
2. Type in a whole number value for i, which can be negative except for Rabbit(i), in the From i= box.
3. If you want to find all the values in a certain range, type a value in the To i= box also.
4. Select an action:
Show series
outputs the numbers in the selected series for i in the chosen range.
Initial digits
Benford's Law relates to the distribution of the initial digits of Fibonacci and Lucas numbers. (Precision buttons are ignored.)
Amaze me!
produces a correct, random expression equal to 1 and involving two nth-roots, as mentioned on The Lucas numbers page.
Clear all
clears all values and the output area.

### BROWSER:

This calculator requires JavaScript (not the same as Java!) and Internet Explorer 4 or Netscape Navigator 4 or Communicator 4 or later versions.

#### Netscape Navigator:

Make sure JavaScript is enabled in Navigator version 4 or later:
In Edit Menu - Preferences - Advanced, make sure the box marked 'JavaScript' is checked.

#### Microsoft Internet Explorer 4+

Make sure Scripting is enabled in version 4 or later:
In Edit Menu - Preferences - Web Content, make sure 'Enable Scripting' is checked in the "Active Content" section.

### Eval

The Eval box lets you type in a mathematical expression involving i. It is evaluated in the i range that you give and values printed in the Output area.
NaN means the output is Not a Number (there is an error in your expression, or you've given an impossible value to a function, such as sqrt(-1).
Infinity - the Calculator has generated a value that is too large for it.

E , PI, Phi, phi

#### Operations

+ - * /
% ( x%y is the integer remainder when integer x is divided by integer y)
< > <= >=     equal to is == and not equal to is !=
NB There is no "to-the-power-of" operator - see pow function below.

#### Functions

 abs(x) the absolute value of x (always positive) acos(x) the angle (in radians) whose cosine is x asin(x) the angle (in radians) whose sine is x atan(x) the angle (in radians) whose tangent is x ceil(x) round up to the next integer (if not already an integer) cos(x) the cosine of angle x (x in radians) exp(x) E to the power of x; same as pow(E,x) Fib(i) Fibonacci(i) floor(x) x, if x is an integer, otherwise the next integer less than x log(x) the natural log of x (log to the base E) log10(x) the common log of x (log to base 10) Luc(i) Lucas(i) pow(x,p) xp Rab(i) Rabbit(i) randint(LO,HI) a random integer between LO and HI (inclusive) random() a random number between 0.0 and 1.0 round(x) the nearest integer to x sin(x) the sine of angle x (x in radians) sqrt(x) the square root of x tan(x) the tangent of angle x (x in radians)

#### Conditional Expressions

( C ? T : E ) C is an expression with a true or false result;
T is the value returned if C evaluates to true;
E is the value returned if C evaluates to false