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 | 15 |
| 3 | 90 |
| 4 | 350 |
| 5 | 1050 |
| 6 | 2646 |
| 7 | 5880 |
| 8 | 11880 |
| 9 | 22275 |
| 10 | 39325 |
| 11 | 66066 |
| 12 | 106470 |
| 13 | 165620 |
| 14 | 249900 |
| 15 | 367200 |
| 16 | 527136 |
| 17 | 741285 |
| 18 | 1023435 |
| 19 | 1389850 |
| 20 | 1859550 |
| 21 | 2454606 |
| 22 | 3200450 |
| 23 | 4126200 |
| 24 | 5265000 |
| 25 | 6654375 |
| 26 | 8336601 |
| 27 | 10359090 |
| 28 | 12774790 |
| 29 | 15642600 |
| 30 | 19027800 |