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 | 7 |
| 5 | 28 |
| 6 | 126 |
| 7 | 602 |
| 8 | 2961 |
| 9 | 14805 |
| 10 | 75468 |
| 11 | 389817 |
| 12 | 2037772 |
| 13 | 10758252 |
| 14 | 57287568 |
| 15 | 307324993 |
| 16 | 1659446224 |
| 17 | 9011958240 |
| 18 | 49191458767 |
| 19 | 269736352723 |
| 20 | 1485146234680 |
| 21 | 8207439244571 |
| 22 | 45510032845462 |
| 23 | 253127421288198 |
| 24 | 1411859674966108 |
| 25 | 7895241738604045 |