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 | 4 |
| 3 | 16 |
| 4 | 65 |
| 5 | 268 |
| 6 | 1120 |
| 7 | 4738 |
| 8 | 20265 |
| 9 | 87542 |
| 10 | 381600 |
| 11 | 1677170 |
| 12 | 7427098 |
| 13 | 33118073 |
| 14 | 148618605 |
| 15 | 670849720 |
| 16 | 3044548675 |
| 17 | 13886260129 |
| 18 | 63627798355 |
| 19 | 292789942333 |
| 20 | 1352614829275 |
| 21 | 6271530026012 |
| 22 | 29176789293146 |
| 23 | 136163014291526 |
| 24 | 637294991967740 |