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 | 9 |
| 2 | 81 |
| 3 | 297 |
| 4 | 989 |
| 5 | 3080 |
| 6 | 9994 |
| 7 | 32358 |
| 8 | 104176 |
| 9 | 335940 |
| 10 | 1083914 |
| 11 | 3495930 |
| 12 | 11275444 |
| 13 | 36368274 |
| 14 | 117303034 |
| 15 | 378351488 |
| 16 | 1220339904 |
| 17 | 3936101206 |
| 18 | 12695569864 |
| 19 | 40948497182 |
| 20 | 132075911156 |
| 21 | 425999751988 |
| 22 | 1374026441136 |
| 23 | 4431806698176 |