# negaLucas
> Compute the nth [negaLucas number][lucas-number].
The [negaLucas numbers][lucas-number] are the integer sequence
The sequence is defined by the recurrence relation
which yields
with seed values `L_0 = 2` and `L_{-1} = -1`.
## Usage
```javascript
var negalucas = require( '@stdlib/math/base/special/negalucas' );
```
#### negalucas( n )
Computes the nth [negaLucas number][lucas-number].
```javascript
var v = negalucas( 0 );
// returns 2
v = negalucas( -1 );
// returns -1
v = negalucas( -2 );
// returns 3
v = negalucas( -3 );
// returns -4
v = negalucas( -76 );
// returns 7639424778862807
```
If `n < -76`, the function returns `NaN`, as larger [negaLucas numbers][lucas-number] cannot be safely represented in [double-precision floating-point format][ieee754].
```javascript
var v = negalucas( -77 );
// returns NaN
```
If not provided a nonpositive integer value, the function returns `NaN`.
```javascript
var v = negalucas( -3.14 );
// returns NaN
v = negalucas( 1 );
// returns NaN
```
If provided `NaN`, the function returns `NaN`.
```javascript
var v = negalucas( NaN );
// returns NaN
```
## Examples
```javascript
var negalucas = require( '@stdlib/math/base/special/negalucas' );
var v;
var i;
for ( i = 0; i > -77; i-- ) {
v = negalucas( i );
console.log( v );
}
```
[lucas-number]: https://en.wikipedia.org/wiki/Lucas_number
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
