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 | 636 |
| 5 | 2234 |
| 6 | 6315 |
| 7 | 16812 |
| 8 | 47596 |
| 9 | 129150 |
| 10 | 337186 |
| 11 | 892181 |
| 12 | 2343529 |
| 13 | 6046508 |
| 14 | 15601217 |
| 15 | 40205083 |
| 16 | 102833093 |
| 17 | 262404045 |
| 18 | 669166152 |
| 19 | 1701139222 |
| 20 | 4316129307 |
| 21 | 10943611348 |
| 22 | 27709283328 |
| 23 | 70072708774 |
| 24 | 177098593806 |
| 25 | 447280003769 |