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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 30 |
| 5 | 210 |
| 6 | 2310 |
| 7 | 3570 |
| 8 | 4830 |
| 9 | 11550 |
| 10 | 30030 |
| 11 | 43890 |
| 12 | 111930 |
| 13 | 131670 |
| 14 | 510510 |
| 15 | 690690 |
| 16 | 870870 |
| 17 | 1021020 |
| 18 | 2459730 |
| 19 | 9699690 |
| 20 | 13123110 |
| 21 | 17160990 |
| 22 | 40750710 |
| 23 | 146006070 |
| 24 | 223092870 |
| 25 | 340510170 |
| 26 | 358888530 |
| 27 | 688677990 |
| 28 | 1462190730 |
| 29 | 2445553110 |
| 30 | 2911018110 |
| 31 | 6469693230 |