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 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 6 |
| 5 | 12 |
| 6 | 20 |
| 7 | 48 |
| 8 | 120 |
| 9 | 240 |
| 10 | 540 |
| 11 | 1440 |
| 12 | 4320 |
| 13 | 11520 |
| 14 | 30240 |
| 15 | 64512 |
| 16 | 207360 |
| 17 | 725760 |
| 18 | 2419200 |
| 19 | 7257600 |
| 20 | 17418240 |
| 21 | 39191040 |
| 22 | 174182400 |
| 23 | 696729600 |
| 24 | 2786918400 |
| 25 | 9405849600 |
| 26 | 25082265600 |
| 27 | 65840947200 |
| 28 | 182891520000 |
| 29 | 1003290624000 |
| 30 | 4514807808000 |
| 31 | 21069103104000 |