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 | 3 |
| 2 | 25 |
| 3 | 120 |
| 4 | 420 |
| 5 | 1190 |
| 6 | 2898 |
| 7 | 6300 |
| 8 | 12540 |
| 9 | 23265 |
| 10 | 40755 |
| 11 | 68068 |
| 12 | 109200 |
| 13 | 169260 |
| 14 | 254660 |
| 15 | 373320 |
| 16 | 534888 |
| 17 | 750975 |
| 18 | 1035405 |
| 19 | 1404480 |
| 20 | 1877260 |
| 21 | 2475858 |
| 22 | 3225750 |
| 23 | 4156100 |
| 24 | 5300100 |
| 25 | 6695325 |
| 26 | 8384103 |
| 27 | 10413900 |
| 28 | 12837720 |
| 29 | 15714520 |
| 30 | 19109640 |
| 31 | 23095248 |
| 32 | 27750800 |