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) |
|---|---|
| 1 | 4 |
| 2 | 31 |
| 3 | 225 |
| 4 | 1563 |
| 5 | 10222 |
| 6 | 63030 |
| 7 | 374264 |
| 8 | 2160300 |
| 9 | 12196405 |
| 10 | 67724342 |
| 11 | 371233523 |
| 12 | 2014305995 |
| 13 | 10841722966 |
| 14 | 57974736592 |
| 15 | 308361428628 |
| 16 | 1632877406997 |