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 | 6 |
| 3 | 29 |
| 4 | 132 |
| 5 | 589 |
| 6 | 2613 |
| 7 | 11592 |
| 8 | 51558 |
| 9 | 230181 |
| 10 | 1032060 |
| 11 | 4648150 |
| 12 | 21027765 |
| 13 | 95542878 |
| 14 | 435939525 |
| 15 | 1997076805 |
| 16 | 9183661080 |
| 17 | 42383777344 |
| 18 | 196271453865 |
| 19 | 911804206063 |
| 20 | 4248637465050 |
| 21 | 19852810349837 |
| 22 | 93012949698861 |
| 23 | 436860932671829 |