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 | 3 |
| 2 | 25 |
| 3 | 235 |
| 4 | 2737 |
| 5 | 36947 |
| 6 | 563657 |
| 7 | 9542715 |
| 8 | 176920417 |
| 9 | 3555369635 |
| 10 | 76820077945 |
| 11 | 1772943290763 |
| 12 | 43469116126737 |
| 13 | 1127040956393203 |
| 14 | 30779951676185385 |
| 15 | 882453651485815003 |
| 16 | 26480355971228530369 |
| 17 | 829522636694530362691 |
| 18 | 27064267045022876869337 |
| 19 | 917751849133986186857003 |