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 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 11 |
| 7 | 34 |
| 8 | 124 |
| 9 | 512 |
| 10 | 2380 |
| 11 | 12294 |
| 12 | 69972 |
| 13 | 435399 |
| 14 | 2942672 |
| 15 | 21478882 |
| 16 | 168473955 |
| 17 | 1413823577 |
| 18 | 12644505883 |
| 19 | 120097766639 |
| 20 | 1207617481139 |
| 21 | 12818915877849 |
| 22 | 143278176040760 |
| 23 | 1682262113899134 |
| 24 | 20704109403389717 |
| 25 | 266568690074855277 |
| 26 | 3583926627760681407 |