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 | 3 |
| 3 | 74 |
| 4 | 1220 |
| 5 | 12910 |
| 6 | 100807 |
| 7 | 652343 |
| 8 | 3750182 |
| 9 | 19784428 |
| 10 | 96786947 |
| 11 | 439906101 |
| 12 | 1859501560 |
| 13 | 7328752206 |
| 14 | 27039030100 |
| 15 | 93829708460 |
| 16 | 307762056698 |
| 17 | 958683800155 |
| 18 | 2848583303210 |
| 19 | 8105942966932 |
| 20 | 22169003715353 |
| 21 | 58456685214757 |