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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 27 |
| 5 | 75 |
| 6 | 225 |
| 7 | 651 |
| 8 | 1947 |
| 9 | 5661 |
| 10 | 15753 |
| 11 | 44497 |
| 12 | 128325 |
| 13 | 357339 |
| 14 | 1025029 |
| 15 | 2881677 |
| 16 | 8152327 |
| 17 | 22251081 |
| 18 | 62981541 |
| 19 | 175699737 |
| 20 | 491888331 |
| 21 | 1353494089 |
| 22 | 3827528649 |
| 23 | 10655040429 |
| 24 | 29413393659 |
| 25 | 80737582089 |
| 26 | 226955441541 |
| 27 | 626061311481 |
| 28 | 1745916338341 |
| 29 | 4826531920159 |
| 30 | 13166998285539 |