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 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | 114 |
| 4 | 2652 |
| 5 | 29660 |
| 6 | 198030 |
| 7 | 932862 |
| 8 | 3440024 |
| 9 | 10599192 |
| 10 | 28478970 |
| 11 | 68716010 |
| 12 | 152040372 |
| 13 | 313269684 |
| 14 | 608134982 |
| 15 | 1122341430 |
| 16 | 1983307440 |
| 17 | 3375066032 |
| 18 | 5556852594 |
| 19 | 8885943522 |
| 20 | 13845350540 |
| 21 | 21077015820 |
| 22 | 31421193342 |
| 23 | 45962742254 |
| 24 | 66085098312 |
| 25 | 93532729800 |