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 | 0 |
| 1 | 2 |
| 2 | 10 |
| 3 | 58 |
| 4 | 442 |
| 5 | 4282 |
| 6 | 50362 |
| 7 | 695482 |
| 8 | 11017402 |
| 9 | 196811962 |
| 10 | 3912703162 |
| 11 | 85662309562 |
| 12 | 2047652863162 |
| 13 | 53059407256762 |
| 14 | 1481388530277562 |
| 15 | 44331262220901562 |
| 16 | 1415527220320869562 |
| 17 | 48036189795719781562 |
| 18 | 1726380042510080613562 |
| 19 | 65503446445655792229562 |
| 20 | 2616586102571484256869562 |