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 | 1 |
| 3 | 2 |
| 4 | 2 |
| 5 | 4 |
| 6 | 15 |
| 7 | 25 |
| 8 | 69 |
| 9 | 254 |
| 10 | 1799 |
| 11 | 4039 |
| 12 | 16828 |
| 13 | 61751 |
| 14 | 349831 |
| 15 | 3485031 |
| 16 | 10391139 |
| 17 | 49433136 |
| 18 | 240065255 |
| 19 | 1282012987 |
| 20 | 9167583734 |
| 21 | 131550812011 |
| 22 | 459677216341 |
| 23 | 2707382738559 |
| 24 | 14318807603110 |
| 25 | 94084166753927 |
| 26 | 601900541251447 |
| 27 | 5894253303715375 |