function binomcoefln( n, k ) {
	if ( isnan( n ) || isnan( k ) ) {
		return NaN;
	}
	if ( !isInteger( n ) || !isInteger( k ) ) {
		return NaN;
	}
	if ( n < 0.0 ) {
		return binomcoefln( -n + k - 1, k );
	}
	if ( k < 0 ) {
		return NINF;
	}
	if ( k === 0 ) {
		return 0.0;
	}
	if ( k === 1 ) {
		return ln( abs( n ) );
	}
	if ( n < k ) {
		return NINF;
	}
	if ( n - k < 2 ) {
		return binomcoefln( n, n - k );
	}
	// Case: n - k >= 2
	return -ln( n + 1 ) - betaln( n - k + 1, k + 1 );
}
Computes the natural logarithm of the binomial coefficient of two integers.

@param {integer} n - input value
@param {integer} k - second input value
@returns {number} function value

@example
var v = binomcoefln( 8, 2 );
// returns ~3.332

@example
var v = binomcoefln( 0, 0 );
// returns 0.0

@example
var v = binomcoefln( -4, 2 );
// returns ~2.303

@example
var v = binomcoefln( 88, 3 );
// returns ~11.606

@example
var v = binomcoefln( NaN, 3 );
// returns NaN

@example
var v = binomcoefln( 5, NaN );
// returns NaN

@example
var v = binomcoefln( NaN, NaN );
// returns NaN