This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 10 |
| 4 | 78 |
| 5 | 777 |
| 6 | 9800 |
| 7 | 149796 |
| 8 | 2690420 |
| 9 | 55555500 |
| 10 | 1296871224 |
| 11 | 33773107758 |
| 12 | 970753545580 |
| 13 | 30527491279005 |
| 14 | 1042604500906800 |
| 15 | 38430716820193144 |
| 16 | 1520662246114589640 |
| 17 | 64291516462902839175 |
| 18 | 2892426397164199846860 |
| 19 | 137970526315789473684210 |
| 20 | 6955460736173788715925048 |
| 21 | 369510689788116404049535299 |