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 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 53 |
| 6 | 214 |
| 7 | 958 |
| 8 | 4650 |
| 9 | 24103 |
| 10 | 131974 |
| 11 | 757011 |
| 12 | 4519321 |
| 13 | 27933252 |
| 14 | 177987808 |
| 15 | 1165057411 |
| 16 | 7811122974 |
| 17 | 53506838952 |
| 18 | 373693431140 |
| 19 | 2656088059747 |
| 20 | 19182588092365 |
| 21 | 140577110057850 |
| 22 | 1044102585724522 |
| 23 | 7851149068600037 |
| 24 | 59714190403840142 |
| 25 | 459001044591439621 |