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 | 5 |
| 4 | 15 |
| 5 | 52 |
| 6 | 203 |
| 7 | 877 |
| 8 | 4140 |
| 9 | 21146 |
| 10 | 115964 |
| 11 | 678448 |
| 12 | 4212352 |
| 13 | 27632112 |
| 14 | 190778186 |
| 15 | 1381763398 |
| 16 | 10468226150 |
| 17 | 82744297014 |
| 18 | 680835331228 |
| 19 | 5819712427654 |
| 20 | 51584619782546 |
| 21 | 473344099095848 |
| 22 | 4489677962922186 |
| 23 | 43957668431564086 |
| 24 | 443694809361207824 |