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 | 1 |
| 2 | 6 |
| 3 | 27 |
| 4 | 125 |
| 5 | 635 |
| 6 | 3488 |
| 7 | 20425 |
| 8 | 126817 |
| 9 | 831915 |
| 10 | 5744784 |
| 11 | 41618459 |
| 12 | 315388311 |
| 13 | 2493721645 |
| 14 | 20526285716 |
| 15 | 175529425815 |
| 16 | 1556577220651 |
| 17 | 14290644428279 |
| 18 | 135624265589086 |
| 19 | 1328702240382589 |
| 20 | 13420603191219111 |
| 21 | 139592874355534071 |