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 | 0 |
| 1 | 1 |
| 2 | 0 |
| 3 | 3 |
| 4 | 7 |
| 5 | 16 |
| 6 | 49 |
| 7 | 104 |
| 8 | 322 |
| 9 | 683 |
| 10 | 2114 |
| 11 | 4485 |
| 12 | 13881 |
| 13 | 29450 |
| 14 | 91147 |
| 15 | 193378 |
| 16 | 598500 |
| 17 | 1269781 |
| 18 | 3929940 |
| 19 | 8337783 |
| 20 | 25805227 |
| 21 | 54748516 |
| 22 | 169445269 |
| 23 | 359496044 |
| 24 | 1112631142 |