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 | 3 |
| 2 | 9 |
| 3 | 27 |
| 4 | 69 |
| 5 | 207 |
| 6 | 621 |
| 7 | 3345 |
| 8 | 4275 |
| 9 | 25497 |
| 10 | 38247 |
| 11 | 229173 |
| 12 | 589185 |
| 13 | 1669443 |
| 14 | 5205897 |
| 15 | 14045019 |
| 16 | 34319397 |
| 17 | 102566511 |
| 18 | 307313949 |
| 19 | 1843835217 |
| 20 | 2312645619 |
| 21 | 13776780249 |
| 22 | 20417442711 |
| 23 | 112792132341 |
| 24 | 290155405761 |
| 25 | 847524815523 |
| 26 | 2611222884297 |
| 27 | 7627711248315 |