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 | 2 |
| 2 | 6 |
| 3 | 31 |
| 4 | 180 |
| 5 | 1101 |
| 6 | 6901 |
| 7 | 43828 |
| 8 | 280664 |
| 9 | 1807909 |
| 10 | 11698479 |
| 11 | 75973701 |
| 12 | 494890116 |
| 13 | 3231949644 |
| 14 | 21153128028 |
| 15 | 138712184488 |