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 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 6 |
| 8 | 21 |
| 9 | 56 |
| 10 | 126 |
| 11 | 252 |
| 12 | 2562 |
| 13 | 14442 |
| 14 | 59487 |
| 15 | 199627 |
| 16 | 578005 |
| 17 | 8330800 |
| 18 | 65056960 |
| 19 | 363823800 |
| 20 | 1628423880 |
| 21 | 6190034016 |
| 22 | 115452938151 |
| 23 | 1152005977431 |
| 24 | 8137667253101 |
| 25 | 45527993728141 |
| 26 | 214265281290061 |
| 27 | 4904624749585886 |
| 28 | 59578069604921361 |