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) |
|---|---|
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 2 |
| 7 | 9 |
| 8 | 21 |
| 9 | 78 |
| 10 | 199 |
| 11 | 699 |
| 12 | 1889 |
| 13 | 6491 |
| 14 | 18261 |
| 15 | 62145 |
| 16 | 180091 |
| 17 | 610220 |
| 18 | 1809045 |
| 19 | 6118849 |
| 20 | 18469079 |
| 21 | 62440111 |
| 22 | 191235803 |
| 23 | 646681908 |
| 24 | 2004592956 |
| 25 | 6782895492 |
| 26 | 21239394216 |
| 27 | 71925883149 |
| 28 | 227169634741 |
| 29 | 769998727785 |
| 30 | 2450045838331 |
| 31 | 8312417389237 |
| 32 | 26620229804149 |