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 | 2 |
| 2 | 9 |
| 3 | 32 |
| 4 | 121 |
| 5 | 450 |
| 6 | 1681 |
| 7 | 6272 |
| 8 | 23409 |
| 9 | 87362 |
| 10 | 326041 |
| 11 | 1216800 |
| 12 | 4541161 |
| 13 | 16947842 |
| 14 | 63250209 |
| 15 | 236052992 |
| 16 | 880961761 |
| 17 | 3287794050 |
| 18 | 12270214441 |
| 19 | 45793063712 |
| 20 | 170902040409 |
| 21 | 637815097922 |
| 22 | 2380358351281 |
| 23 | 8883618307200 |
| 24 | 33154114877521 |
| 25 | 123732841202882 |