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 | 0 |
| 1 | 0 |
| 2 | 12 |
| 3 | 92 |
| 4 | 536 |
| 5 | 2872 |
| 6 | 14884 |
| 7 | 75924 |
| 8 | 384048 |
| 9 | 1933424 |
| 10 | 9706556 |
| 11 | 48650956 |
| 12 | 243609160 |
| 13 | 1219108776 |
| 14 | 6098732628 |
| 15 | 30503229188 |
| 16 | 152544843872 |
| 17 | 762810312928 |
| 18 | 3814309845100 |
| 19 | 19072324066620 |
| 20 | 95363944856184 |
| 21 | 476826697849880 |