# negaFibonacci
> Compute the nth [negaFibonacci number][fibonacci-number].
The [negaFibonacci numbers][fibonacci-number] are the integer sequence
The sequence is defined by the recurrence relation
which yields
with seed values `F_0 = 0` and `F_{-1} = 1`.
## Usage
```javascript
var negafibonacci = require( '@stdlib/math/base/special/negafibonacci' );
```
#### negafibonacci( n )
Computes the nth [negaFibonacci number][fibonacci-number].
```javascript
var v = negafibonacci( 0 );
// returns 0
v = negafibonacci( -1 );
// returns 1
v = negafibonacci( -2 );
// returns -1
v = negafibonacci( -3 );
// returns 2
v = negafibonacci( -78 );
// returns -8944394323791464
```
If `n < -78`, the function returns `NaN`, as larger [negaFibonacci numbers][fibonacci-number] cannot be safely represented in [double-precision floating-point format][ieee754].
```javascript
var v = negafibonacci( -79 );
// returns NaN
```
If not provided a nonpositive integer value, the function returns `NaN`.
```javascript
var v = negafibonacci( -3.14 );
// returns NaN
v = negafibonacci( 1 );
// returns NaN
```
If provided `NaN`, the function returns `NaN`.
```javascript
var v = negafibonacci( NaN );
// returns NaN
```
## Examples
```javascript
var negafibonacci = require( '@stdlib/math/base/special/negafibonacci' );
var v;
var i;
for ( i = 0; i > -79; i-- ) {
v = negafibonacci( i );
console.log( v );
}
```
[fibonacci-number]: https://en.wikipedia.org/wiki/Fibonacci_number
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
