\\ A361832
a(n) = {
	my (d = digits(n, 3), t = vector(#d));
	for (k = 1, #d,
		t[k] = d[1];
		d = vector(#d-1, i, (-d[i]-d[i+1])%3);
	);
	fromdigits(t, 3);
}

is(n) = n==a(n)

{
	m = 0;

	print (m++ " " 0);

	ff = [1,2];
	while (m < 10 000,
		apply (f -> print (m++ " " f), ff);

		ff = select(is, concat(apply(f -> [3*f, 3*f+1, 3*f+2], ff)));
	);
}

quit