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 | 3 |
| 2 | 9 |
| 3 | 40 |
| 4 | 192 |
| 5 | 993 |
| 6 | 5375 |
| 7 | 30081 |
| 8 | 172650 |
| 9 | 1010640 |
| 10 | 6010530 |
| 11 | 36214656 |
| 12 | 220590082 |
| 13 | 1356131892 |
| 14 | 8403647454 |
| 15 | 52436122717 |
| 16 | 329170499604 |
| 17 | 2077465903503 |
| 18 | 13173914483799 |
| 19 | 83897445169341 |
| 20 | 536355204428412 |
| 21 | 3440875097256529 |
| 22 | 22144300030907667 |