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 | 2 |
| 2 | 3 |
| 3 | 6 |
| 4 | 22 |
| 5 | 147 |
| 6 | 1443 |
| 7 | 18250 |
| 8 | 280394 |
| 9 | 5063363 |
| 10 | 105063363 |
| 11 | 2463011054 |
| 12 | 64380375278 |
| 13 | 1856540769315 |
| 14 | 58550453144611 |
| 15 | 2004745521503986 |
| 16 | 74062339559431922 |
| 17 | 2936485391069247715 |
| 18 | 124376016487663499491 |