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 | 3 |
| 2 | 10 |
| 3 | 36 |
| 4 | 138 |
| 5 | 558 |
| 6 | 2364 |
| 7 | 10440 |
| 8 | 47868 |
| 9 | 227124 |
| 10 | 1112184 |
| 11 | 5607792 |
| 12 | 29057400 |
| 13 | 154465704 |
| 14 | 841143312 |
| 15 | 4685949792 |
| 16 | 26674999056 |
| 17 | 155000193840 |
| 18 | 918475565472 |
| 19 | 5545430185536 |
| 20 | 34087326300576 |
| 21 | 213170582612448 |
| 22 | 1355345600149440 |
| 23 | 8755789617922176 |
| 24 | 57440317657203648 |