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 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 0 |
| 5 | 5 |
| 6 | 0 |
| 7 | 12 |
| 8 | 0 |
| 9 | 20 |
| 10 | 0 |
| 11 | -30 |
| 12 | 0 |
| 13 | -546 |
| 14 | 0 |
| 15 | -3672 |
| 16 | 0 |
| 17 | -18796 |
| 18 | 0 |
| 19 | -79640 |
| 20 | 0 |
| 21 | -270955 |
| 22 | 0 |
| 23 | -584340 |
| 24 | 0 |
| 25 | 903396 |
| 26 | 0 |
| 27 | 20471948 |
| 28 | 0 |
| 29 | 155046180 |
| 30 | 0 |
| 31 | 872787888 |
| 32 | 0 |
| 33 | 4012121412 |
| 34 | 0 |
| 35 | 14728928136 |
| 36 | 0 |
| 37 | 34982326212 |
| 38 | 0 |
| 39 | -40695186320 |
| 40 | 0 |
| 41 | -1194336566976 |
| 42 | 0 |
| 43 | -9612277504606 |
| 44 | 0 |
| 45 | -56604770338290 |
| 46 | 0 |