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 | 35 |
| 1 | 66 |
| 2 | 180 |
| 3 | 660 |
| 4 | 2904 |
| 5 | 14196 |
| 6 | 73920 |
| 7 | 400620 |
| 8 | 2229624 |
| 9 | 12637956 |
| 10 | 72573360 |
| 11 | 420738780 |
| 12 | 2456635944 |
| 13 | 14422057716 |
| 14 | 85023813600 |
| 15 | 502907704140 |
| 16 | 2982460443864 |
| 17 | 17724476245476 |
| 18 | 105513644666640 |
| 19 | 628987635392700 |
| 20 | 3753738850485384 |
| 21 | 22422625749793236 |
| 22 | 134041199563164480 |