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 | 1 |
| 2 | 5 |
| 3 | 25 |
| 4 | 125 |
| 5 | 646 |
| 6 | 3395 |
| 7 | 18054 |
| 8 | 96885 |
| 9 | 523600 |
| 10 | 2845700 |
| 11 | 15537457 |
| 12 | 85160387 |
| 13 | 468279280 |
| 14 | 2582140370 |
| 15 | 14272523740 |
| 16 | 79056303957 |
| 17 | 438711518556 |
| 18 | 2438587839980 |
| 19 | 13574970187300 |
| 20 | 75668677723100 |
| 21 | 422294150816010 |
| 22 | 2359326605275755 |
| 23 | 13194525668986350 |
| 24 | 73857744668632275 |