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 | -264 |
| 2 | 30564 |
| 3 | -2012800 |
| 4 | 81099090 |
| 5 | -1952940672 |
| 6 | 22697326712 |
| 7 | 63468624384 |
| 8 | -4486982088465 |
| 9 | 11373493964160 |
| 10 | 616923039055284 |
| 11 | -663002527580928 |
| 12 | -77516928995402226 |
| 13 | -352040146340083200 |
| 14 | 5929423960701095640 |
| 15 | 87636971447313802240 |
| 16 | 269600086946598203619 |