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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 28 |
| 4 | 183 |
| 5 | 1401 |
| 6 | 12466 |
| 7 | 127443 |
| 8 | 1478581 |
| 9 | 19239274 |
| 10 | 277797577 |
| 11 | 4409962349 |
| 12 | 76355817104 |
| 13 | 1432117088325 |
| 14 | 28925947345561 |
| 15 | 625973017346996 |
| 16 | 14449435509751843 |
| 17 | 354384392492622789 |
| 18 | 9202836581079864186 |
| 19 | 252260861877820739167 |
| 20 | 7278710020682729662089 |