22221: Near Repdigit 22..221

First few terms (base 10): \[[2^*1_9]_n=\{1,19,181,1639,14761,\ldots\}\]

First few terms (base 9): \[\{\text{1},\text{21},\text{221},\text{2221},\text{22221},\ldots\}\]

General Formula:\[[2^*1_9]_n={9\cdot9^{n}-5\over4}\]

Equivalent Patterns: \[[4^*2_9]_n=2\cdot[2^*1_9]_n\] \[[8^*4_9]_n=4\cdot[2^*1_9]_n\] \[[6^*3_9]_n=3\cdot[2^*1_9]_n\]

Table

No table data.