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 | 1 |
| 3 | 0 |
| 4 | 2 |
| 5 | 1 |
| 6 | 0 |
| 7 | 6 |
| 8 | 8 |
| 9 | 1 |
| 10 | 0 |
| 11 | 24 |
| 12 | 58 |
| 13 | 22 |
| 14 | 1 |
| 15 | 0 |
| 16 | 120 |
| 17 | 444 |
| 18 | 328 |
| 19 | 52 |
| 20 | 1 |
| 21 | 0 |
| 22 | 720 |
| 23 | 3708 |
| 24 | 4400 |
| 25 | 1452 |
| 26 | 114 |
| 27 | 1 |
| 28 | 0 |
| 29 | 5040 |
| 30 | 33984 |
| 31 | 58140 |
| 32 | 32120 |
| 33 | 5610 |
| 34 | 240 |
| 35 | 1 |
| 36 | 0 |
| 37 | 40320 |
| 38 | 341136 |
| 39 | 785304 |
| 40 | 644020 |
| 41 | 195800 |
| 42 | 19950 |
| 43 | 494 |
| 44 | 1 |
| 45 | 0 |
| 46 | 362880 |
| 47 | 3733920 |
| 48 | 11026296 |
| 49 | 12440064 |
| 50 | 5765500 |
| 51 | 1062500 |