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 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 129 |
| 5 | 270 |
| 6 | 833 |
| 7 | 5044 |
| 8 | 59815 |
| 9 | 9633693 |
| 10 | 26427528 |
| 11 | 4642779313 |
| 12 | 26594615202 |
| 13 | 62935243460 |
| 14 | 91770096041 |
| 15 | 1648209018135 |