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) |
|---|---|
| 2 | 0 |
| 3 | 3 |
| 4 | 16 |
| 5 | 75 |
| 6 | 336 |
| 7 | 1463 |
| 8 | 6240 |
| 9 | 26199 |
| 10 | 108640 |
| 11 | 445995 |
| 12 | 1815792 |
| 13 | 7341347 |
| 14 | 29505840 |
| 15 | 117982815 |
| 16 | 469672384 |
| 17 | 1862393775 |
| 18 | 7359403968 |
| 19 | 28991540051 |
| 20 | 113892526800 |
| 21 | 446305331451 |
| 22 | 1744950085648 |
| 23 | 6808253393415 |
| 24 | 26513475730464 |
| 25 | 103072540115975 |
| 26 | 400058834841120 |