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 | 0 |
| 2 | 1 |
| 3 | 6 |
| 4 | 27 |
| 5 | 112 |
| 6 | 450 |
| 7 | 1782 |
| 8 | 7007 |
| 9 | 27456 |
| 10 | 107406 |
| 11 | 419900 |
| 12 | 1641486 |
| 13 | 6418656 |
| 14 | 25110020 |
| 15 | 98285670 |
| 16 | 384942375 |
| 17 | 1508593920 |
| 18 | 5915896470 |
| 19 | 23213240820 |
| 20 | 91140287370 |
| 21 | 358042932000 |
| 22 | 1407342229020 |
| 23 | 5534695100220 |
| 24 | 21777424274502 |
| 25 | 85729014099072 |
| 26 | 337635166767500 |