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 | 3 |
| 2 | 12 |
| 3 | 41 |
| 4 | 144 |
| 5 | 498 |
| 6 | 1728 |
| 7 | 5985 |
| 8 | 20736 |
| 9 | 71831 |
| 10 | 248832 |
| 11 | 861979 |
| 12 | 2985984 |
| 13 | 10343751 |
| 14 | 35831808 |
| 15 | 124125023 |
| 16 | 429981696 |
| 17 | 1489500287 |
| 18 | 5159780352 |
| 19 | 17874003451 |
| 20 | 61917364224 |
| 21 | 214488041413 |
| 22 | 743008370688 |