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) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 30 |
| 3 | 115 |
| 4 | 425 |
| 5 | 1396 |
| 6 | 4440 |
| 7 | 13470 |
| 8 | 40000 |
| 9 | 116140 |
| 10 | 332827 |
| 11 | 942435 |
| 12 | 2647450 |
| 13 | 7386925 |
| 14 | 20511620 |
| 15 | 56731383 |
| 16 | 156451985 |
| 17 | 430462915 |
| 18 | 1182341890 |
| 19 | 3243215495 |
| 20 | 8887664047 |
| 21 | 24338341165 |
| 22 | 66616422775 |
| 23 | 182276901760 |
| 24 | 498657609720 |
| 25 | 1364083988834 |