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 | 3 |
| 3 | 9 |
| 4 | 33 |
| 5 | 135 |
| 6 | 633 |
| 7 | 3207 |
| 8 | 17589 |
| 9 | 102627 |
| 10 | 636033 |
| 11 | 4161140 |
| 12 | 28680694 |
| 13 | 207317854 |
| 14 | 1567337840 |
| 15 | 12345045176 |
| 16 | 101012326346 |
| 17 | 856192424564 |
| 18 | 7501633169738 |
| 19 | 67811887289162 |
| 20 | 631523439500196 |
| 21 | 6051299254375782 |
| 22 | 59595920426107182 |
| 23 | 602637812152552784 |
| 24 | 6251230070001558400 |