0 isn't a node_id (we prefer the underscore). IDs in our little universe start at 1, so we don't have to be bothered to worry about exists-but-false, so node_id=0 is equivalent to not giving a node ID at all, so you end up at the default node, which happens to be 131, not terribly low at all.

17 is in fact the not found node, and isn't messed up at all; it's supposed to be like that.

1 is the nodetype nodetype. That is, the type of a node is also a node, and 1 is the type that the types of nodes are. I hope that was as clear as mud; I want to maintain an air of mystery, because it's more fun that way.

...and along that lines, I'm not going to tell you what the rest are. Insert maniacal laughter here.