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 | 4 |
| 2 | 13 |
| 3 | 38 |
| 4 | 135 |
| 5 | 677 |
| 6 | 3538 |
| 7 | 15868 |
| 8 | 63313 |
| 9 | 268430 |
| 10 | 1348190 |
| 11 | 7038185 |
| 12 | 33328258 |
| 13 | 144159428 |
| 14 | 642323050 |
| 15 | 3213846836 |
| 16 | 16700677289 |
| 17 | 80935833050 |
| 18 | 363843867265 |
| 19 | 1660048399600 |
| 20 | 8276473557820 |
| 21 | 42830085070355 |
| 22 | 210286731046320 |
| 23 | 967456811687945 |
| 24 | 4476690297795850 |