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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 4 |
| 8 | 10 |
| 9 | 34 |
| 10 | 96 |
| 11 | 284 |
| 12 | 782 |
| 13 | 2226 |
| 14 | 6208 |
| 15 | 17560 |
| 16 | 49618 |
| 17 | 141500 |
| 18 | 405104 |
| 19 | 1168316 |
| 20 | 3386538 |
| 21 | 9875232 |
| 22 | 28939944 |
| 23 | 85235762 |
| 24 | 252159572 |
| 25 | 749160544 |
| 26 | 2234378156 |
| 27 | 6688358338 |
| 28 | 20088296030 |
| 29 | 60524845158 |
| 30 | 182893018756 |