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 | 0 |
| 2 | 2 |
| 3 | 2 |
| 4 | 13 |
| 5 | 34 |
| 6 | 158 |
| 7 | 594 |
| 8 | 2665 |
| 9 | 11558 |
| 10 | 53320 |
| 11 | 247488 |
| 12 | 1181266 |
| 13 | 5708884 |
| 14 | 28049474 |
| 15 | 139417402 |
| 16 | 701063005 |
| 17 | 3559326294 |
| 18 | 18233244530 |
| 19 | 94140532624 |
| 20 | 489573775236 |
| 21 | 2562613997512 |
| 22 | 13493827469116 |
| 23 | 71441865994904 |