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 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 30 |
| 5 | 104 |
| 6 | 390 |
| 7 | 1518 |
| 8 | 6208 |
| 9 | 26372 |
| 10 | 116221 |
| 11 | 529341 |
| 12 | 2487054 |
| 13 | 12027502 |
| 14 | 59778867 |
| 15 | 304916272 |
| 16 | 1594273763 |
| 17 | 8535706749 |
| 18 | 46753269749 |
| 19 | 261771468438 |
| 20 | 1497087288210 |
| 21 | 8739579074131 |
| 22 | 52045067963540 |
| 23 | 315980654042243 |
| 24 | 1954770128712348 |
| 25 | 12315770916526091 |