For any k, the cumulative sum a(1) + a(2) + a(3) + ... + a(k) shares at least five digits with a(k). Lexicographically first sequence of positive integers without duplicate terms having this property.

A326640

For any k, the cumulative sum a(1) + a(2) + a(3) + ... + a(k) shares at least five digits with a(k). Lexicographically first sequence of positive integers without duplicate terms having this property.