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) |
|---|---|
| 3 | 1 |
| 4 | 15 |
| 5 | 155 |
| 6 | 1395 |
| 7 | 11811 |
| 8 | 97155 |
| 9 | 788035 |
| 10 | 6347715 |
| 11 | 50955971 |
| 12 | 408345795 |
| 13 | 3269560515 |
| 14 | 26167664835 |
| 15 | 209386049731 |
| 16 | 1675267338435 |
| 17 | 13402854502595 |
| 18 | 107225699266755 |
| 19 | 857817047249091 |
| 20 | 6862582190715075 |
| 21 | 54900840777134275 |
| 22 | 439207459223777475 |