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 | 0 |
| 2 | 6 |
| 3 | 9 |
| 4 | 84 |
| 5 | 375 |
| 6 | 1998 |
| 7 | 11361 |
| 8 | 60840 |
| 9 | 299403 |
| 10 | 1368930 |
| 11 | 5906373 |
| 12 | 24362748 |
| 13 | 97019247 |
| 14 | 375712470 |
| 15 | 1422455625 |
| 16 | 5286155088 |
| 17 | 19340722707 |
| 18 | 69831127242 |
| 19 | 249265052301 |
| 20 | 880927979940 |
| 21 | 3086000399223 |
| 22 | 10726216043070 |
| 23 | 37020328044945 |
| 24 | 126961071656184 |
| 25 | 432900077950875 |