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 | 9 |
| 1 | 16 |
| 2 | 50 |
| 3 | 180 |
| 4 | 686 |
| 5 | 2688 |
| 6 | 10692 |
| 7 | 42900 |
| 8 | 173030 |
| 9 | 700128 |
| 10 | 2838524 |
| 11 | 11522056 |
| 12 | 46802700 |
| 13 | 190182400 |
| 14 | 772913160 |
| 15 | 3141129780 |
| 16 | 12764118870 |
| 17 | 51857916000 |
| 18 | 210638666700 |
| 19 | 855355383960 |
| 20 | 3472419702180 |
| 21 | 14092569803520 |
| 22 | 57176602275000 |
| 23 | 231908298827400 |
| 24 | 940340123399196 |
| 25 | 3811765978738368 |