7,111,111,111,117

[Math.]

8×8+13 = 77      

88×8+13 = 717

888×8+13 = 7117

8888×8+13 = 71117

88,888×8+13 = 711,117

888,888×8+13 = 7,111,117

8,888,888×8+13 = 71,111,117

88,888,888×8+13 = 711,111,117

888,888,888×8+13 = 7,111,111,117

8,888,888,888×8+13 = 71,111,111,117

88,888,888,888×8+13 = 711,111,111,117

888,888,888,888×8+13 = 7,111,111,111,117

8,888,888,888,888×8+13 = 77,111,111,111,117

88,888,888,888,888×8+13 = 777,111,111,111,117

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