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 | 0 |
| 1 | 3 |
| 2 | 30 |
| 3 | 135 |
| 4 | 452 |
| 5 | 1295 |
| 6 | 3378 |
| 7 | 8295 |
| 8 | 19560 |
| 9 | 44847 |
| 10 | 100790 |
| 11 | 223223 |
| 12 | 488940 |
| 13 | 1061775 |
| 14 | 2289882 |
| 15 | 4910535 |
| 16 | 10480208 |
| 17 | 22275695 |
| 18 | 47178270 |
| 19 | 99605847 |
| 20 | 209704980 |
| 21 | 440390223 |
| 22 | 922733570 |
| 23 | 1929364775 |
| 24 | 4026514872 |