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 | 2 |
| 4 | 5 |
| 5 | 13 |
| 6 | 49 |
| 7 | 201 |
| 8 | 940 |
| 9 | 4643 |
| 10 | 24037 |
| 11 | 127859 |
| 12 | 696365 |
| 13 | 3858759 |
| 14 | 21704863 |
| 15 | 123619126 |
| 16 | 711787259 |
| 17 | 4137614454 |
| 18 | 24256010068 |
| 19 | 143271593982 |
| 20 | 852001881614 |
| 21 | 5097719884665 |
| 22 | 30670572676389 |
| 23 | 185466705697057 |