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) |
|---|---|
| 0 | 2 |
| 1 | 3 |
| 2 | 10 |
| 3 | 5 |
| 4 | 28 |
| 5 | 252 |
| 6 | 840 |
| 7 | 7 |
| 8 | 88 |
| 9 | 23760 |
| 10 | 22 |
| 11 | 330 |
| 12 | 66528 |
| 13 | 23760 |
| 14 | 6652800 |
| 15 | 11 |
| 16 | 208 |
| 17 | 468 |
| 18 | 471744000 |
| 19 | 390 |
| 20 | 58240 |
| 21 | 1872 |
| 22 | 468 |
| 23 | 163800 |
| 24 | 93600 |
| 25 | 39 |
| 26 | 3736212480000 |
| 27 | 39000 |
| 28 | 17472 |
| 29 | 94152554496000 |
| 30 | 313841848320000 |
| 31 | 13 |
| 32 | 544 |
| 33 | 7387354275840000 |
| 34 | 146880 |
| 35 | 84823200 |
| 36 | 68 |
| 37 | 36720 |
| 38 | 12337920 |
| 39 | 1079568000 |