tr(v)=if (v>=0, 1+2*v, -2*v)

ord = [0]


{
	z = 0;	\\ wanted
	v = 0;
	for (n = 0, oo,
		if (v==z,
			print (z " " n);
			if (z==10 000,
					break,
					z++
			);
		);

		w = tr(v);
		while (#ord < w,
			ord = concat(ord, vector(#ord));
		);

		k = ord[w]++;
		e = v > 0;

		v += (-1)^(k+e)*(k\2);
	);
}