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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 6 |
| 5 | 21 |
| 6 | 86 |
| 7 | 371 |
| 8 | 1647 |
| 9 | 7438 |
| 10 | 34266 |
| 11 | 159927 |
| 12 | 755533 |
| 13 | 3604684 |
| 14 | 17347231 |
| 15 | 84103279 |
| 16 | 410421861 |
| 17 | 2014380304 |
| 18 | 9937355972 |
| 19 | 49247272198 |
| 20 | 245062080990 |
| 21 | 1223998706732 |
| 22 | 6134070857861 |
| 23 | 30835493057217 |
| 24 | 155444304401138 |
| 25 | 785636444084278 |
| 26 | 3980190985058791 |