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 | 3 |
| 3 | 9 |
| 4 | 33 |
| 5 | 135 |
| 6 | 633 |
| 7 | 3206 |
| 8 | 17574 |
| 9 | 102444 |
| 10 | 634004 |
| 11 | 4139104 |
| 12 | 28450444 |
| 13 | 204936318 |
| 14 | 1542796630 |
| 15 | 12090425696 |
| 16 | 98341974504 |
| 17 | 827789394188 |
| 18 | 7194985058192 |
| 19 | 64450636832800 |
| 20 | 594124150130062 |
| 21 | 5628903025067656 |
| 22 | 54753047168362054 |
| 23 | 546261960780208350 |
| 24 | 5584759231202910230 |