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 | 1 |
| 1 | 1 |
| 2 | 12 |
| 3 | 133 |
| 4 | 1475 |
| 5 | 16358 |
| 6 | 181413 |
| 7 | 2011901 |
| 8 | 22312324 |
| 9 | 247447465 |
| 10 | 2744234439 |
| 11 | 30434026294 |
| 12 | 337518523673 |
| 13 | 3743137786697 |
| 14 | 41512034177340 |
| 15 | 460375513737437 |
| 16 | 5105642685289147 |
| 17 | 56622445051918054 |
| 18 | 627952538256387741 |
| 19 | 6964100365872183205 |
| 20 | 77233056562850402996 |