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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 4 |
| 5 | 26 |
| 6 | 120 |
| 7 | 455 |
| 8 | 1456 |
| 9 | 4122 |
| 10 | 10608 |
| 11 | 25194 |
| 12 | 55980 |
| 13 | 117572 |
| 14 | 235144 |
| 15 | 450681 |
| 16 | 832048 |
| 17 | 1485800 |
| 18 | 2575368 |
| 19 | 4345965 |
| 20 | 7158060 |
| 21 | 11532402 |
| 22 | 18209100 |
| 23 | 28224105 |
| 24 | 43008120 |
| 25 | 64512240 |
| 26 | 95365920 |
| 27 | 139075245 |
| 28 | 200268432 |
| 29 | 284997384 |
| 30 | 401107356 |