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 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 22 |
| 6 | 75 |
| 7 | 267 |
| 8 | 1119 |
| 9 | 4965 |
| 10 | 22694 |
| 11 | 117090 |
| 12 | 670621 |
| 13 | 3866503 |
| 14 | 24113829 |
| 15 | 161085223 |
| 16 | 1120025702 |
| 17 | 8121648620 |
| 18 | 62083083115 |
| 19 | 492273775141 |
| 20 | 4074919882483 |