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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 20 |
| 6 | 70 |
| 7 | 256 |
| 8 | 969 |
| 9 | 3762 |
| 10 | 14894 |
| 11 | 59904 |
| 12 | 244088 |
| 13 | 1005452 |
| 14 | 4180096 |
| 15 | 17516936 |
| 16 | 73913705 |
| 17 | 313774854 |
| 18 | 1339162028 |
| 19 | 5742691704 |
| 20 | 24731501410 |
| 21 | 106919054880 |
| 22 | 463844340060 |
| 23 | 2018673093000 |
| 24 | 8810852089650 |
| 25 | 38558866555248 |