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 | 5 |
| 3 | 20 |
| 4 | 96 |
| 5 | 469 |
| 6 | 3145 |
| 7 | 20684 |
| 8 | 173544 |
| 9 | 1557105 |
| 10 | 16215253 |
| 11 | 159346604 |
| 12 | 2230085528 |
| 13 | 26985045333 |
| 14 | 368730610729 |
| 15 | 5628888393652 |
| 16 | 97987283458928 |
| 17 | 1475486672174337 |
| 18 | 29097611462122437 |
| 19 | 505383110562327268 |
| 20 | 10970329921706735216 |