GEN
bfile(GEN name, GEN v, GEN offset)
{
	pari_sp ltop = avma;
	GEN cur = gen_0, Anum = gen_0;
	// If no v is given, fine; but if it is it must be a vector.
	// Should this use is_vec_t(typ(v)) to allow t_COL as well?
	if (v && typ(v) != t_VEC)
		pari_err(typeer, "bfile");
	if (!offset)
		offset = gen_1;
	else if (typ(offset) != t_INT)
		pari_err(typeer, "bfile");
	cur = subis(offset, 1);
	
	if (typ(name) == t_INT)
	{
		name = gtovec(GENtoGENstr(name));
		GEN p2;
		while (glength(name) < 6)
		{
			p2 = cgetg(2, t_VEC);
			gel(p2, 1) = strtoGENstr("0");
			name = concat(p2, name);
		}
		Anum = concat(name, NULL);	// "0","0","0","0","4","0" -> "000040"
		name = concat(concat(strtoGENstr("b"), Anum), strtoGENstr(".txt"));
	} else {
		if (typ(name) != t_STR)
			pari_err(typeer, "bfile");
		// TODO: Try to extract a reasonable A-number, or just set to blank?
		Anum = strtoGENstr("000000");
		//Anum = concat(extract0(gtovec(name), stoi(126), NULL), NULL);
	}
	
	char* filename = GSTR(name);
	if (!v)
		return bfilein(filename);
	FILE *f = fopen(filename, "r");
	if (f)
		pari_warn(warner, "File `%Ps' already exists. Appending terms..", name);
	
	long l1 = lg(v);
	pari_sp btop = avma, st_lim = stack_lim(btop, 1);
	long i;
	for (i = 1; i < l1; ++i)
	{
		GEN e = gel(v, i);
		if (typ(e) != t_INT)
			pari_err(typeer, "bfile");
		if (cmpis(digits(e), 1000) > 0)
		{
			pari_warn(warner, "Next term has %Ps digits; exiting.\n", digits(e));
			break;
		}
		write0(filename, mkvec3(cur = addis(cur, 1), strtoGENstr(" "), e));
		if (low_stack(st_lim, stack_lim(btop, 1)))
			cur = gerepilecopy(btop, cur);
	}
	pari_printf("%%H A%Ps Author, <a href=\"b%Ps.txt\">Table of n, a(n) for n = %Ps..%Ps</a>\n", Anum, Anum, offset, cur);
	avma = ltop;
	return gnil;
}