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 | 6 |
| 3 | 36 |
| 4 | 228 |
| 5 | 1545 |
| 6 | 11196 |
| 7 | 86457 |
| 8 | 708504 |
| 9 | 6136830 |
| 10 | 55976430 |
| 11 | 535904259 |
| 12 | 5369146272 |
| 13 | 56145107577 |
| 14 | 611336534802 |
| 15 | 6916529431620 |
| 16 | 81152874393168 |
| 17 | 985767316792449 |
| 18 | 12376996566040980 |
| 19 | 160399065135692073 |