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 | 4 |
| 3 | 26 |
| 4 | 232 |
| 5 | 2624 |
| 6 | 35888 |
| 7 | 575280 |
| 8 | 10569984 |
| 9 | 218911872 |
| 10 | 5044346112 |
| 11 | 127980834816 |
| 12 | 3544627393536 |
| 13 | 106408500206592 |
| 14 | 3441351475359744 |
| 15 | 119279906031888384 |
| 16 | 4410902376303722496 |
| 17 | 173335758665503997952 |
| 18 | 7213199863532804702208 |
| 19 | 316878056718379090771968 |