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 | 3 |
| 3 | 13 |
| 4 | 76 |
| 5 | 427 |
| 6 | 2427 |
| 7 | 13871 |
| 8 | 79729 |
| 9 | 460473 |
| 10 | 2670394 |
| 11 | 15540822 |
| 12 | 90717305 |
| 13 | 530946697 |
| 14 | 3114680815 |
| 15 | 18308774295 |
| 16 | 107817336510 |
| 17 | 635942014275 |
| 18 | 3756423495198 |
| 19 | 22217666030882 |
| 20 | 131563775350068 |