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 | 3 |
| 2 | 12 |
| 3 | 51 |
| 4 | 216 |
| 5 | 903 |
| 6 | 3732 |
| 7 | 15291 |
| 8 | 62256 |
| 9 | 252303 |
| 10 | 1019052 |
| 11 | 4105731 |
| 12 | 16511496 |
| 13 | 66311703 |
| 14 | 266043972 |
| 15 | 1066567371 |
| 16 | 4273443936 |
| 17 | 17115299103 |
| 18 | 68525766492 |
| 19 | 274296776211 |
| 20 | 1097768235576 |
| 21 | 4392816334503 |
| 22 | 17576495514612 |
| 23 | 70321672588251 |