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 | 12 |
| 4 | 40 |
| 5 | 130 |
| 6 | 404 |
| 7 | 1227 |
| 8 | 3653 |
| 9 | 10720 |
| 10 | 31090 |
| 11 | 89316 |
| 12 | 254568 |
| 13 | 720757 |
| 14 | 2029095 |
| 15 | 5684340 |
| 16 | 15855964 |
| 17 | 44061862 |
| 18 | 122032508 |
| 19 | 336966015 |
| 20 | 927953705 |
| 21 | 2549229256 |
| 22 | 6987648358 |
| 23 | 19115124552 |
| 24 | 52194037200 |
| 25 | 142274514025 |
| 26 | 387215773899 |