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 | 4 |
| 2 | 16 |
| 3 | 64 |
| 4 | 416 |
| 5 | 4544 |
| 6 | 23488 |
| 7 | -207616 |
| 8 | 4205056 |
| 9 | 198295552 |
| 10 | -2574439424 |
| 11 | -112886362112 |
| 12 | 3567419838464 |
| 13 | 94446596145152 |
| 14 | -5636771173998592 |
| 15 | -80736001427931136 |
| 16 | 11035864514607054848 |
| 17 | 15012780903941799936 |
| 18 | -25650368909583695740928 |