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 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 19 |
| 5 | 165 |
| 6 | 1801 |
| 7 | 24003 |
| 8 | 378379 |
| 9 | 6880485 |
| 10 | 141757201 |
| 11 | 3263757123 |
| 12 | 83046239299 |
| 13 | 2314209491685 |
| 14 | 70093262093401 |
| 15 | 2292753819807363 |
| 16 | 80548997707137979 |
| 17 | 3024937662747436965 |
| 18 | 120925183043471954401 |
| 19 | 5127013172890341294723 |
| 20 | 229794790034059392232819 |