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 | 0 |
| 1 | 2 |
| 2 | 8 |
| 3 | 24 |
| 4 | 72 |
| 5 | 240 |
| 6 | 924 |
| 7 | 4116 |
| 8 | 20944 |
| 9 | 119952 |
| 10 | 763540 |
| 11 | 5346748 |
| 12 | 40845816 |
| 13 | 338041704 |
| 14 | 3012855356 |
| 15 | 28770647220 |
| 16 | 293055401888 |
| 17 | 3171602665696 |
| 18 | 36343889387172 |
| 19 | 439607533130732 |
| 20 | 5597256953340360 |
| 21 | 74829813397495128 |
| 22 | 1048039052970587788 |
| 23 | 15345654816688856484 |