function tribonaccif( n ) {
	return addon( n );
}
Computes the nth Tribonacci number as a single-precision floating-point number.

@private
@param {NonNegativeInteger} n - the Tribonacci number to compute
@returns {NonNegativeInteger} Tribonacci number

@example
var y = tribonaccif( 0 );
// returns 0

@example
var y = tribonaccif( 1 );
// returns 0

@example
var y = tribonaccif( 2 );
// returns 1

@example
var y = tribonaccif( 3 );
// returns 1

@example
var y = tribonaccif( 4 );
// returns 2

@example
var y = tribonaccif( 5 );
// returns 4

@example
var y = tribonaccif( 6 );
// returns 7

@example
var y = tribonaccif( -1 );
// returns NaN