[PE 535] Fractal Sequence

參考資料：https://en.wikipedia.org/wiki/Fractal_sequence

原題目：https://projecteuler.net/problem=535

Definition: If the first occurrence of each n is deleted, the remaining sequence is identical to the original. The process can be repeated indefinitely, so that actually, the original sequence contains not only one copy of itself, but rather, infinitely many.

碎形的定義就是自我重複。碎形數列也會有自我重複的特質。題目要求計算 T({10}^{18})，看來與 non-circled numbers 定義有很大的關係。