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 | 10 |
| 2 | 21 |
| 3 | 62 |
| 4 | 247 |
| 5 | 1202 |
| 6 | 7201 |
| 7 | 50401 |
| 8 | 403201 |
| 9 | 3628801 |
| 10 | 36288001 |
| 11 | 399168002 |
| 12 | 4790016001 |
| 13 | 62270208001 |
| 14 | 871782912007 |
| 15 | 130767436800017 |
| 16 | 209227898880001 |
| 17 | 3556874280960001 |
| 18 | 64023737057280001 |
| 19 | 12164510040883200031 |