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) |
|---|---|
| 1 | 30 |
| 2 | 140 |
| 3 | 2480 |
| 4 | 6200 |
| 5 | 40640 |
| 6 | 297600 |
| 7 | 997920 |
| 8 | 64995840 |
| 9 | 167751680 |
| 10 | 1502582400 |
| 11 | 42949345280 |
| 12 | 183196016640 |
| 13 | 687193456640 |
| 14 | 1447428787200 |
| 15 | 63870637017600 |
| 16 | 326676430080000 |
| 17 | 20797363851264000 |
| 18 | 24871926476966400 |
| 19 | 42981218625945600 |
| 20 | 404918548479244800 |