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) |
|---|---|
| 2 | 5 |
| 3 | 12 |
| 4 | 66 |
| 5 | 215 |
| 6 | 789 |
| 7 | 2597 |
| 8 | 8540 |
| 9 | 27153 |
| 10 | 85135 |
| 11 | 262482 |
| 12 | 799566 |
| 13 | 2408718 |
| 14 | 7189343 |
| 15 | 21282450 |
| 16 | 62550312 |
| 17 | 182664881 |
| 18 | 530391339 |
| 19 | 1532152571 |
| 20 | 4405406030 |
| 21 | 12613400079 |
| 22 | 35974991437 |
| 23 | 102242458164 |
| 24 | 289632199980 |
| 25 | 818005152300 |
| 26 | 2303856458345 |
| 27 | 6471890313480 |
| 28 | 18136792078398 |