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 | 4 |
| 2 | 36 |
| 3 | 204 |
| 4 | 980 |
| 5 | 3876 |
| 6 | 13596 |
| 7 | 42636 |
| 8 | 122666 |
| 9 | 326876 |
| 10 | 817388 |
| 11 | 1931540 |
| 12 | 4346404 |
| 13 | 9360540 |
| 14 | 19390548 |
| 15 | 38779380 |
| 16 | 75136675 |
| 17 | 141430680 |
| 18 | 259292440 |
| 19 | 463991880 |
| 20 | 811990680 |
| 21 | 1391975640 |
| 22 | 2341057896 |
| 23 | 3867821640 |
| 24 | 6285222804 |
| 25 | 10056336264 |