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 | 15 |
| 2 | 47 |
| 3 | 131 |
| 4 | 343 |
| 5 | 863 |
| 6 | 2111 |
| 7 | 5055 |
| 8 | 11903 |
| 9 | 27647 |
| 10 | 63487 |
| 11 | 144383 |
| 12 | 325631 |
| 13 | 729087 |
| 14 | 1622015 |
| 15 | 3588095 |
| 16 | 7897087 |
| 17 | 17301503 |
| 18 | 37748735 |
| 19 | 82051071 |
| 20 | 177733631 |
| 21 | 383778815 |
| 22 | 826277887 |
| 23 | 1774190591 |
| 24 | 3800039423 |
| 25 | 8120172543 |
| 26 | 17314086911 |
| 27 | 36842766335 |
| 28 | 78248935423 |