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 | 2 |
| 3 | 8 |
| 4 | 44 |
| 5 | 308 |
| 6 | 2612 |
| 7 | 25988 |
| 8 | 296564 |
| 9 | 3816548 |
| 10 | 54667412 |
| 11 | 862440068 |
| 12 | 14857100084 |
| 13 | 277474957988 |
| 14 | 5584100659412 |
| 15 | 120462266974148 |
| 16 | 2772968936479604 |
| 17 | 67843210855558628 |
| 18 | 1757952715142990612 |
| 19 | 48093560991292628228 |