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 | 2 |
| 2 | 7 |
| 3 | 28 |
| 4 | 139 |
| 5 | 762 |
| 6 | 4549 |
| 7 | 28464 |
| 8 | 184742 |
| 9 | 1230348 |
| 10 | 8362298 |
| 11 | 57756888 |
| 12 | 404218046 |
| 13 | 2860222020 |
| 14 | 20428192842 |
| 15 | 147072637472 |
| 16 | 1066221149519 |
| 17 | 7776835940430 |
| 18 | 57028407361537 |
| 19 | 420199462347876 |
| 20 | 3109418928328473 |
| 21 | 23098206138595710 |
| 22 | 172184651286785655 |
| 23 | 1287629984135461888 |