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 | 221 |
| 4 | 536 |
| 5 | 1711 |
| 6 | 4993 |
| 7 | 16742 |
| 8 | 53411 |
| 9 | 182247 |
| 10 | 608142 |
| 11 | 2095301 |
| 12 | 7157363 |
| 13 | 24822376 |
| 14 | 85845073 |
| 15 | 299033933 |
| 16 | 1040987192 |
| 17 | 3636447903 |
| 18 | 12703622001 |
| 19 | 44454269798 |
| 20 | 155590727603 |
| 21 | 545028524023 |
| 22 | 1909557999406 |
| 23 | 6693157243061 |