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 | 20 |
| 2 | 400 |
| 3 | 3000 |
| 4 | 14000 |
| 5 | 49000 |
| 6 | 141120 |
| 7 | 352800 |
| 8 | 792000 |
| 9 | 1633500 |
| 10 | 3146000 |
| 11 | 5725720 |
| 12 | 9937200 |
| 13 | 16562000 |
| 14 | 26656000 |
| 15 | 41616000 |
| 16 | 63256320 |
| 17 | 93896100 |
| 18 | 136458000 |
| 19 | 194579000 |
| 20 | 272734000 |
| 21 | 376372920 |
| 22 | 512072000 |
| 23 | 687700000 |
| 24 | 912600000 |
| 25 | 1197787500 |