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) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 16 |
| 6 | 56 |
| 7 | 208 |
| 8 | 804 |
| 9 | 3202 |
| 10 | 13046 |
| 11 | 54120 |
| 12 | 227812 |
| 13 | 970596 |
| 14 | 4177436 |
| 15 | 18136008 |
| 16 | 79326641 |
| 17 | 349241700 |
| 18 | 1546401412 |
| 19 | 6882164584 |
| 20 | 30767887372 |
| 21 | 138114569908 |
| 22 | 622270344740 |
| 23 | 2812994557488 |
| 24 | 12755010576700 |
| 25 | 57996678526684 |