allocate mem(2^30);

is(n) = {
	n%2==0 && n>2 && hammingweight(n)%2==1
}
back(n) = {
	my (v=0, b=binary(n+1), x=0);
	forstep (k=#b, 1, -1,
		b[k] = x=bitxor(x, b[k]);
	);
	fromdigits(b, 2);
}

{
	k=-1;
	for (n=0, 26,
		print ("#"n);
		if (n==0,
				r = [1],
				r = setunion(2*r, Set(apply(back, select(is, r))))
		);

		apply(v -> print (k++ " " v), r);
	);
}

quit