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 | 4 |
| 1 | 4 |
| 2 | 4 |
| 3 | 4 |
| 4 | 0 |
| 5 | -12 |
| 6 | -32 |
| 7 | -52 |
| 8 | -52 |
| 9 | 0 |
| 10 | 136 |
| 11 | 356 |
| 12 | 576 |
| 13 | 576 |
| 14 | 0 |
| 15 | -1508 |
| 16 | -3948 |
| 17 | -6388 |
| 18 | -6388 |
| 19 | 0 |
| 20 | 16724 |
| 21 | 43784 |
| 22 | 70844 |
| 23 | 70844 |
| 24 | 0 |
| 25 | -185472 |
| 26 | -485572 |
| 27 | -785672 |
| 28 | -785672 |
| 29 | 0 |
| 30 | 2056916 |
| 31 | 5385076 |
| 32 | 8713236 |
| 33 | 8713236 |
| 34 | 0 |
| 35 | -22811548 |
| 36 | -59721408 |
| 37 | -96631268 |
| 38 | -96631268 |
| 39 | 0 |
| 40 | 252983944 |
| 41 | 662320564 |