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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 7 |
| 6 | 33 |
| 7 | 106 |
| 8 | 563 |
| 9 | 1232 |
| 10 | 1795 |
| 11 | 8412 |
| 12 | 18619 |
| 13 | 27031 |
| 14 | 153774 |
| 15 | 6793087 |
| 16 | 6946861 |
| 17 | 34580531 |
| 18 | 41527392 |
| 19 | 117635315 |
| 20 | 512068652 |
| 21 | 629703967 |
| 22 | 1141772619 |
| 23 | 1771476586 |
| 24 | 9999155549 |
| 25 | 141759654272 |
| 26 | 151758809821 |
| 27 | 7729700145322 |
| 28 | 116097260989651 |