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 | 9 |
| 1 | 0 |
| 2 | 126 |
| 3 | 144 |
| 4 | 1179 |
| 5 | 2556 |
| 6 | 10332 |
| 7 | 29952 |
| 8 | 109053 |
| 9 | 293580 |
| 10 | 1221390 |
| 11 | 3269736 |
| 12 | 12652155 |
| 13 | 36719028 |
| 14 | 126768168 |
| 15 | 392732064 |
| 16 | 1284178329 |
| 17 | 4104726084 |
| 18 | 13312704402 |
| 19 | 42563828232 |
| 20 | 138178786131 |
| 21 | 439049042172 |
| 22 | 1420005679128 |