11511: Near Repdigit Palindrome 11..11511..11

First few terms (base 10): \[[1^*51^*_7]_n=\{5,85,2997,138629,6735205,\ldots\}\]

First few terms (base 7): \[\{\text{5},\text{151},\text{11511},\text{1115111},\text{111151111},\ldots\}\]

General Formula:\[[1^*51^*_7]_n={7\cdot7^{2n}+24\cdot7^{n}-1\over6}\]

Equivalent Patterns: (none)

Table

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