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 | 3 |
| 3 | 5 |
| 4 | 15 |
| 5 | 61 |
| 6 | 207 |
| 7 | 881 |
| 8 | 4491 |
| 9 | 21493 |
| 10 | 117543 |
| 11 | 710021 |
| 12 | 4266279 |
| 13 | 28107745 |
| 14 | 196120515 |
| 15 | 1397747525 |
| 16 | 10648637151 |
| 17 | 84304440685 |
| 18 | 688868927151 |
| 19 | 5913133211249 |
| 20 | 52348170504555 |
| 21 | 479326416322933 |
| 22 | 4557380168574135 |
| 23 | 44560107679838549 |
| 24 | 449806788855058407 |
| 25 | 4680686977970550721 |