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 | 2 |
| 1 | 1 |
| 2 | 48 |
| 3 | 331 |
| 4 | 2490 |
| 5 | 94500 |
| 6 | 1283805 |
| 7 | 1402294 |
| 8 | 12238270 |
| 9 | 891573671 |
| 10 | 975688072 |
| 11 | 77612456753 |
| 12 | 715763987889 |
| 13 | 748327378591 |
| 14 | 6944174236934 |
| 15 | 580400102242316 |
| 16 | 5209104353769836 |
| 17 | 5710407472211223 |
| 18 | 510579443617388387 |
| 19 | 4806424039483242581 |
| 20 | 45763276831811185976 |
| 21 | 440594267900327752100 |