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 | 2 |
| 2 | 12 |
| 3 | 30 |
| 4 | 5040 |
| 5 | 132 |
| 6 | 43680 |
| 7 | 306 |
| 8 | 175560 |
| 9 | 271252800 |
| 10 | 870 |
| 11 | 1402410240 |
| 12 | 2193360 |
| 13 | 1722 |
| 14 | 3916440 |
| 15 | 14658134400 |
| 16 | 29142257760 |
| 17 | 3540 |
| 18 | 65418312960 |
| 19 | 22005480 |
| 20 | 5112 |
| 21 | 184933148400 |
| 22 | 41977440 |
| 23 | 390190489920 |
| 24 | 5346472978828800 |
| 25 | 94109400 |
| 26 | 10302 |
| 27 | 119224560 |
| 28 | 11556 |
| 29 | 149059680 |
| 30 | 120140035685601494718355200000 |
| 31 | 272613120 |