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 | 4 |
| 1 | 24 |
| 2 | 112 |
| 3 | 480 |
| 4 | 1984 |
| 5 | 8064 |
| 6 | 32512 |
| 7 | 130560 |
| 8 | 523264 |
| 9 | 2095104 |
| 10 | 8384512 |
| 11 | 33546240 |
| 12 | 134201344 |
| 13 | 536838144 |
| 14 | 2147418112 |
| 15 | 8589803520 |
| 16 | 34359476224 |
| 17 | 137438429184 |
| 18 | 549754765312 |
| 19 | 2199021158400 |
| 20 | 8796088827904 |
| 21 | 35184363700224 |
| 22 | 140737471578112 |
| 23 | 562949919866880 |