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 | 7 |
| 4 | 27 |
| 5 | 138 |
| 6 | 900 |
| 7 | 7110 |
| 8 | 66150 |
| 9 | 708120 |
| 10 | 8573040 |
| 11 | 115781400 |
| 12 | 1725154200 |
| 13 | 28103922000 |
| 14 | 496799503200 |
| 15 | 9469060801200 |
| 16 | 193546022670000 |