In Hamlet's Mill, the seminal 1969 examination of the transmission of ancient wisdom through myth, written by Giorgio de Santillana and Hertha von Dechend, the authors cite the Grimnismal, the "sayings of Grimnir," in the Old Norse Poetic Edda, as an example of esoteric myth containing a surprising hidden precessional number.

They write:
It is known that in the final battle of the gods, the massed legions on the side of "order" are the dead warriors, the "Einherier" who once fell in combat on earth and who have been transferred by the Valkyries to reside with Odin in Valhalla -- a theme much rehearsed in heroic poetry.  On the last day, they issue forth to battle in martial array.  Says the Grimnismal (23): "Five hundred gates and forty more -- are in the mighty building of Walhalla -- eight hundred 'Einherier' come out of each one gate -- on the time they go out in defence against the Wolf."  That makes 432,000 in all, a number of significance from of old.  162.
You can read the passage yourself online in the 1936 translation by Henry Bellows here.  His translation is slightly different from that used in Hamlet's Mill, and reads:
23. Five hundred doors | and forty there are,
I ween, in Valhall's walls;
Eight hundred fighters | through one door fare
When to war with the wolf they go.
Interestingly enough, that translation has always reminded me of a significant passage in the beloved tale by J.R.R. Tolkien (1882 - 1973) which first came to the attention of a publisher in the same year (1936), none other than The Hobbit: or There and Back Again.   

As everyone knows (or almost everyone, and the rest will soon enough, with the release of a much-anticipated movie version by Peter Jackson), the plot of that adventure involves regaining the mighty halls of Thror (King under the Mountain) from the dragon Smaug.  Vital to the plans of the thirteen dwarves and the hobbit Bilbo Baggins is the knowledge of a secret door, disclosed on a map made by Thror which is revealed to Thror's grandson Thorin by Gandalf inside the parlour of Bilbo's hobbit-hole.

Take a look at the runes above and listen to Gandalf's translation and see if they do not remind you somewhat of the cadence of the description of Valhalla's doors in Grimnismal 23:
"Five feet high the door and three may walk abreast," say the runes, but Smaug could not creep into a hole that size, not even when he was a young dragon, certainly not after devouring so many of the dwarves and men of Dale.  26.
While it may not seem like a direct parallel, it is a fact that in addition to authoring The Hobbit and the Lord of the Rings trilogy, Tolkien was a respected scholar of Old English and an Oxford Professor, and he acknowledged the influence of Old Norse and Old English sources upon his own fiction, including the influence of the Poetic Edda

I believe it is highly likely that this important passage from the Grimnismal lent its cadence to the description of the size of the secret door in The Hobbit.

The encoding of the important precessional number 432 in the ancient Eddas is discussed in context in the video "Precession = The Key" if you want a fuller discussion of the connection between the doors of Valhalla and the celestial mechanics of the circling skies above us.

As it turns out, Professor Tolkien used another clear reference to a very important "precessional" figure in his Middle Earth books, and that is his reference to Earendil, who -- it turns out -- is none other than Orion, who is Osiris (for more on those connections, see also "Leo, the Lion King, Hamlet and Osiris."  The fact that Tolkien clearly borrowed the name Earendil lends some support to the assertion that his runic description of the secret door in the Lonely Mountain may also have had influences from early poetic texts, texts which he clearly loved and devoted much study towards.

Incidentally, it is also clear that he created the story of The Hobbit prior to the publication of the 1936 translation of the Grimnismal quoted above, so it is almost certain that he had his own personal translation of the Eddas, perhaps even including the formulation of "eight hundred can walk abreast."

In any event, it is an interesting connection for anyone who loves The Hobbit, and it makes one wonder how much else J.R.R. Tolkien knew about precession and the esoteric encoding of ancient knowledge in the stories of "myth."