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 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 108 |
| 5 | 1240 |
| 6 | 16980 |
| 7 | 267624 |
| 8 | 4750872 |
| 9 | 93615408 |
| 10 | 2026018980 |
| 11 | 47764893000 |
| 12 | 1218621868200 |
| 13 | 33459133580496 |
| 14 | 983950866169544 |
| 15 | 30862364045494800 |
| 16 | 1028656519404191280 |
| 17 | 36312294166359724128 |
| 18 | 1353561646509338629572 |
| 19 | 53133041579508472510728 |