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 | 1 |
| 2 | 4 |
| 3 | 27 |
| 4 | 250 |
| 5 | 2935 |
| 6 | 41676 |
| 7 | 693798 |
| 8 | 13242762 |
| 9 | 285008223 |
| 10 | 6826605520 |
| 11 | 180084705031 |
| 12 | 5187350461800 |
| 13 | 161993077533092 |
| 14 | 5451141889485852 |
| 15 | 196629624309733488 |
| 16 | 7568494925621640330 |
| 17 | 309628452894632990415 |
| 18 | 13415755128012445232100 |