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 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 26 |
| 5 | 156 |
| 6 | 1234 |
| 7 | 12340 |
| 8 | 150994 |
| 9 | 2204112 |
| 10 | 37617314 |
| 11 | 738465620 |
| 12 | 16451763834 |
| 13 | 411281292920 |
| 14 | 11427727238034 |
| 15 | 350040470610996 |
| 16 | 11736423864328466 |
| 17 | 428080429306305136 |
| 18 | 16893650334361392866 |