s = 0
unseen = 0
seen(v) = bit test(s, v)
see(v) = s = bit or(s, 2^v); while (seen(unseen), unseen++)

d = vector(2^13)

{
	for (n=0, #d-1,
		print (n " " v=unseen);

		d[n+1] = v;
		forstep (k=n, 1, -1,
			d[k] = bitxor(d[k],d[k+1]);
		);
		for (k=1, n+1,
			see(d[k]);
		);
	);
}

quit