22122: Near Repdigit Palindrome 22..22122..22

First few terms (base 10): \[[2^*12^*_7]_n=\{1,107,5553,274171,13448801,\ldots\}\]

First few terms (base 7): \[\{\text{1},\text{212},\text{22122},\text{2221222},\text{222212222},\ldots\}\]

General Formula:\[[2^*12^*_7]_n={7\cdot7^{2n}-3\cdot7^{n}-1\over3}\]

Equivalent Patterns: \[[6^*36^*_7]_n=3\cdot[2^*12^*_7]_n\] \[[4^*24^*_7]_n=2\cdot[2^*12^*_7]_n\]

Table

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