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 | 0 |
| 2 | 0 |
| 3 | 6 |
| 4 | 63 |
| 5 | 306 |
| 6 | 1038 |
| 7 | 2844 |
| 8 | 6750 |
| 9 | 14437 |
| 10 | 28521 |
| 11 | 52911 |
| 12 | 93258 |
| 13 | 157509 |
| 14 | 256581 |
| 15 | 405171 |
| 16 | 622719 |
| 17 | 934542 |
| 18 | 1373158 |
| 19 | 1979820 |
| 20 | 2806281 |
| 21 | 3916812 |
| 22 | 5390496 |
| 23 | 7323822 |
| 24 | 9833604 |
| 25 | 13060251 |
| 26 | 17171415 |
| 27 | 22366045 |
| 28 | 28878876 |
| 29 | 36985383 |
| 30 | 47007231 |