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 | 0 |
| 2 | 9 |
| 3 | 40 |
| 4 | 108 |
| 5 | 660 |
| 6 | 4032 |
| 7 | 19521 |
| 8 | 89469 |
| 9 | 449550 |
| 10 | 2308554 |
| 11 | 11454129 |
| 12 | 56190429 |
| 13 | 279105021 |
| 14 | 1393420077 |
| 15 | 6924459960 |
| 16 | 34329680172 |
| 17 | 170475275106 |
| 18 | 847412314182 |
| 19 | 4209930190557 |
| 20 | 20905557159789 |
| 21 | 103832641922175 |
| 22 | 515806878937563 |