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 | 21 |
| 3 | 84 |
| 4 | 330 |
| 5 | 1291 |
| 6 | 5052 |
| 7 | 19784 |
| 8 | 77500 |
| 9 | 303608 |
| 10 | 1189372 |
| 11 | 4659245 |
| 12 | 18252027 |
| 13 | 71500068 |
| 14 | 280092848 |
| 15 | 1097230105 |
| 16 | 4298267549 |
| 17 | 16837948391 |
| 18 | 65960645632 |
| 19 | 258392925744 |
| 20 | 1012223324455 |
| 21 | 3965263584006 |
| 22 | 15533444957104 |
| 23 | 60850409347588 |
| 24 | 238374187312038 |