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 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 102 |
| 6 | 609 |
| 7 | 4260 |
| 8 | 34075 |
| 9 | 306670 |
| 10 | 3066692 |
| 11 | 33733610 |
| 12 | 404803314 |
| 13 | 5262443074 |
| 14 | 73674203025 |
| 15 | 1105113045374 |
| 16 | 17681808725979 |
| 17 | 300590748341642 |
| 18 | 5410633470149548 |
| 19 | 102802035932841396 |
| 20 | 2056040718656827910 |
| 21 | 43176855091793386107 |
| 22 | 949890812019454494354 |