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 | 4 |
| 2 | 21 |
| 3 | 75 |
| 4 | 450 |
| 5 | 1729 |
| 6 | 7233 |
| 7 | 36148 |
| 8 | 139855 |
| 9 | 645733 |
| 10 | 2919837 |
| 11 | 11900426 |
| 12 | 55182313 |
| 13 | 238587617 |
| 14 | 1020077489 |
| 15 | 4627613220 |
| 16 | 19831142375 |
| 17 | 86874931360 |
| 18 | 386104242606 |
| 19 | 1664229710205 |
| 20 | 7344843690603 |
| 21 | 32253553194721 |
| 22 | 140150173949016 |