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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 13 |
| 5 | 50 |
| 6 | 221 |
| 7 | 882 |
| 8 | 3613 |
| 9 | 14450 |
| 10 | 58141 |
| 11 | 232562 |
| 12 | 931613 |
| 13 | 3726450 |
| 14 | 14911261 |
| 15 | 59645042 |
| 16 | 238602013 |
| 17 | 954408050 |
| 18 | 3817719581 |
| 19 | 15270878322 |
| 20 | 61083862813 |
| 21 | 244335451250 |
| 22 | 977343203101 |
| 23 | 3909372812402 |
| 24 | 15637496842013 |