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 | 2 |
| 1 | 3 |
| 2 | 12 |
| 3 | 63 |
| 4 | 378 |
| 5 | 2457 |
| 6 | 16848 |
| 7 | 120042 |
| 8 | 880308 |
| 9 | 6602310 |
| 10 | 50417640 |
| 11 | 390736710 |
| 12 | 3065780340 |
| 13 | 24307258410 |
| 14 | 194458067280 |
| 15 | 1567818167445 |
| 16 | 12726994535730 |
| 17 | 103937122041795 |
| 18 | 853378475711580 |
| 19 | 7040372424620535 |
| 20 | 58334514375427290 |