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 | 5 |
| 2 | 20 |
| 3 | 71 |
| 4 | 238 |
| 5 | 770 |
| 6 | 2436 |
| 7 | 7590 |
| 8 | 23397 |
| 9 | 71566 |
| 10 | 217646 |
| 11 | 659022 |
| 12 | 1988805 |
| 13 | 5986176 |
| 14 | 17980968 |
| 15 | 53922096 |
| 16 | 161492571 |
| 17 | 483149385 |
| 18 | 1444245936 |
| 19 | 4314214443 |
| 20 | 12880107548 |
| 21 | 38436170366 |
| 22 | 114657076900 |
| 23 | 341926185770 |
| 24 | 1019435748435 |
| 25 | 3038815305981 |
| 26 | 9056974493700 |