tonegafib(n) = {
	my (v=0, neg=0, pos=0, f);
	for (e=0, oo,
		f=fibonacci(-1-e);
		if (f<0, neg+=f, pos+=f);
		if (neg <=n && n <= pos,
			while (n,
				if (f<0, neg-=f, pos-=f);
				if (neg > n || n > pos,
					v+=2^e;
					n-=f;
				);
				f=fibonacci(-1-e--);
			);
			return (v);
		);
	);
}

fromnegafib(n) = {
	my (v=0, e);
	while (n,
		n-=2^e=valuation(n, 2);
		v+=fibonacci(-1-e);
	);
	return (v);
}

a(n) = {
	if (n==0,
			0,
			my (f=tonegafib(n),
				z=valuation(f,2),
				r=2^z * fromdigits(Vecrev(binary(f/2^z)),2));
			fromnegafib(r);
	);
}

for (n=0, fibonacci(21)-1, print (n " ", -a(-n)))

quit