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 | 283 |
| 4 | 987 |
| 5 | 3866 |
| 6 | 13494 |
| 7 | 44730 |
| 8 | 150608 |
| 9 | 498551 |
| 10 | 1615388 |
| 11 | 5213924 |
| 12 | 16743300 |
| 13 | 53330410 |
| 14 | 169085209 |
| 15 | 534330613 |
| 16 | 1682097877 |
| 17 | 5278749205 |
| 18 | 16525845242 |
| 19 | 51617974464 |
| 20 | 160893899363 |
| 21 | 500630178086 |
| 22 | 1555278833939 |
| 23 | 4824719777577 |