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 | 9 |
| 2 | 25 |
| 3 | 71 |
| 4 | 203 |
| 5 | 583 |
| 6 | 1679 |
| 7 | 4845 |
| 8 | 14001 |
| 9 | 40503 |
| 10 | 117263 |
| 11 | 339699 |
| 12 | 984515 |
| 13 | 2854281 |
| 14 | 8277153 |
| 15 | 24007543 |
| 16 | 69642819 |
| 17 | 202046535 |
| 18 | 586220911 |
| 19 | 1700972653 |
| 20 | 4935747673 |
| 21 | 14322646039 |
| 22 | 41562779655 |
| 23 | 120613013891 |
| 24 | 350017652003 |
| 25 | 1015758270153 |