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 | 1 |
| 2 | 36 |
| 3 | 630 |
| 4 | 6512 |
| 5 | 45628 |
| 6 | 239316 |
| 7 | 1007083 |
| 8 | 3570240 |
| 9 | 11042199 |
| 10 | 30569012 |
| 11 | 77221232 |
| 12 | 180646896 |
| 13 | 395884866 |
| 14 | 820217412 |
| 15 | 1618520277 |
| 16 | 3060257024 |
| 17 | 5572071725 |
| 18 | 9810869508 |
| 19 | 16763347626 |
| 20 | 27879160048 |
| 21 | 45246275592 |
| 22 | 71818632820 |
| 23 | 111707913791 |
| 24 | 170553162816 |
| 25 | 255984075075 |