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 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 1 |
| 6 | 9 |
| 7 | 6 |
| 8 | 1 |
| 9 | 40 |
| 10 | 60 |
| 11 | 24 |
| 12 | 1 |
| 13 | 195 |
| 14 | 560 |
| 15 | 420 |
| 16 | 120 |
| 17 | 1 |
| 18 | 1056 |
| 19 | 5550 |
| 20 | 6240 |
| 21 | 3240 |
| 22 | 720 |
| 23 | 1 |
| 24 | 6321 |
| 25 | 59472 |
| 26 | 94710 |
| 27 | 68880 |
| 28 | 27720 |
| 29 | 5040 |
| 30 | 1 |
| 31 | 41392 |
| 32 | 692440 |
| 33 | 1527456 |
| 34 | 1426320 |
| 35 | 792960 |
| 36 | 262080 |
| 37 | 40320 |
| 38 | 1 |
| 39 | 293607 |
| 40 | 8753040 |
| 41 | 26418168 |
| 42 | 30560544 |
| 43 | 21213360 |
| 44 | 9676800 |
| 45 | 2721600 |
| 46 | 362880 |
| 47 | 1 |
| 48 | 2237920 |
| 49 | 119723130 |
| 50 | 490458240 |
| 51 | 691331760 |
| 52 | 570810240 |
| 53 | 323114400 |
| 54 | 125798400 |
| 55 | 30844800 |
| 56 | 3628800 |