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 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 12 |
| 4 | 30 |
| 5 | 60 |
| 6 | 210 |
| 7 | 840 |
| 8 | 2520 |
| 9 | 7560 |
| 10 | 27720 |
| 11 | 83160 |
| 12 | 240240 |
| 13 | 840840 |
| 14 | 2702700 |
| 15 | 10810800 |
| 16 | 36756720 |
| 17 | 122522400 |
| 18 | 465585120 |
| 19 | 1551950400 |
| 20 | 4888643760 |
| 21 | 19554575040 |
| 22 | 74959204320 |
| 23 | 257002986240 |
| 24 | 936990054000 |
| 25 | 3480248772000 |
| 26 | 11745839605500 |
| 27 | 40477970332800 |
| 28 | 146732642456400 |
| 29 | 524045151630000 |