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) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 10 |
| 3 | 111 |
| 4 | 1220 |
| 5 | 13421 |
| 6 | 147630 |
| 7 | 1623931 |
| 8 | 17863240 |
| 9 | 196495641 |
| 10 | 2161452050 |
| 11 | 23775972551 |
| 12 | 261535698060 |
| 13 | 2876892678661 |
| 14 | 31645819465270 |
| 15 | 348104014117971 |
| 16 | 3829144155297680 |
| 17 | 42120585708274481 |
| 18 | 463326442791019290 |
| 19 | 5096590870701212191 |
| 20 | 56062499577713334100 |