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 | 4 |
| 3 | 12 |
| 4 | 37 |
| 5 | 123 |
| 6 | 440 |
| 7 | 1686 |
| 8 | 6901 |
| 9 | 30085 |
| 10 | 139212 |
| 11 | 681336 |
| 12 | 3515397 |
| 13 | 19064135 |
| 14 | 108370384 |
| 15 | 644142962 |
| 16 | 3994439189 |
| 17 | 25789465377 |
| 18 | 173033812804 |
| 19 | 1204425693988 |
| 20 | 8683782562597 |
| 21 | 64757730613875 |
| 22 | 498827437211176 |
| 23 | 3964154812486062 |
| 24 | 32463601480302005 |
| 25 | 273670283527555869 |