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) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 19 |
| 5 | 101 |
| 6 | 1776 |
| 7 | 23717 |
| 8 | 515971 |
| 9 | 11893597 |
| 10 | 346475728 |
| 11 | 11497161545 |
| 12 | 444592761746 |
| 13 | 19536147771219 |
| 14 | 970739908493421 |
| 15 | 54010183143383066 |
| 16 | 3341831947578263267 |
| 17 | 228462339968313577341 |
| 18 | 17160142419913160027448 |
| 19 | 1409008382280004776187961 |