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 | 3 |
| 2 | 1 |
| 3 | 1 |
| 4 | 761 |
| 5 | 61 |
| 6 | 509 |
| 7 | 1171733 |
| 8 | 8431 |
| 9 | 39541 |
| 10 | 55835135 |
| 11 | 36093 |
| 12 | 1347822955 |
| 13 | 34395742267 |
| 14 | 375035183 |
| 15 | 9682292227 |
| 16 | 586061125622639 |
| 17 | 54062195834749 |
| 18 | 40030624861 |
| 19 | 2053580969474233 |
| 20 | 1236275063173 |
| 21 | 6657281227331 |