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 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 51 |
| 6 | 195 |
| 7 | 932 |
| 8 | 5651 |
| 9 | 43641 |
| 10 | 428905 |
| 11 | 5362388 |
| 12 | 85303080 |
| 13 | 1726416461 |
| 14 | 44444215422 |
| 15 | 1455335603434 |
| 16 | 60619535173748 |
| 17 | 3211914908993651 |
| 18 | 216474718772864071 |
| 19 | 18558435268379931580 |
| 20 | 2023812522812259857355 |