“So there are seven planets, each has seven by seven conditions, so written in hermetism, 777.
In cryptography the seven in units means globes, in tens it means rounds, in hundreds it means planets. These figures have to be multiplicated.
Therefore our planet system has to undergo 7 by 7 by 7 or 343 metamorphoses.” (Rudolf Steiner)
Source. Rudolf Steiner, “Vor dem Tore der Theosophie”, Neunter Vortrag, GA095, S. 86