# Lucas Number
> Maximum safe nth [Lucas number][lucas-number] when stored in [double-precision floating-point][ieee754] format.
## Usage
```javascript
var FLOAT64_MAX_SAFE_NTH_LUCAS = require( '@stdlib/constants/float64/max-safe-nth-lucas' );
```
#### FLOAT64_MAX_SAFE_NTH_LUCAS
The maximum [safe][safe-integers] nth [Lucas number][lucas-number] when stored in [double-precision floating-point][ieee754] format.
```javascript
var bool = ( FLOAT64_MAX_SAFE_NTH_LUCAS === 76 );
// returns true
```
## Examples
```javascript
var FLOAT64_MAX_SAFE_NTH_LUCAS = require( '@stdlib/constants/float64/max-safe-nth-lucas' );
var v;
var i;
function lucas( n ) {
var a;
var b;
var c;
var i;
a = 2;
if ( n === 0 ) {
return a;
}
b = 1;
for ( i = 2; i <= n; i++ ) {
c = a + b;
a = b;
b = c;
}
return b;
}
for ( i = 0; i < 100; i++ ) {
v = lucas( i );
if ( i > FLOAT64_MAX_SAFE_NTH_LUCAS ) {
console.log( 'Unsafe: %d', v );
} else {
console.log( 'Safe: %d', v );
}
}
```
[safe-integers]: http://www.2ality.com/2013/10/safe-integers.html
[lucas-number]: https://en.wikipedia.org/wiki/Lucas_number
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985