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 | 3 |
| 2 | 3 |
| 3 | -27 |
| 4 | -189 |
| 5 | -567 |
| 6 | 189 |
| 7 | 11259 |
| 8 | 59859 |
| 9 | 129033 |
| 10 | -395847 |
| 11 | -4730481 |
| 12 | -19580211 |
| 13 | -21264201 |
| 14 | 258785523 |
| 15 | 1917734373 |
| 16 | 6051991059 |
| 17 | -2659507911 |
| 18 | -135544952151 |
| 19 | -738957668337 |
| 20 | -1618780564359 |
| 21 | 5297724346923 |
| 22 | 63513121347063 |
| 23 | 266379249285873 |
| 24 | 286776522444861 |
| 25 | -3683959713627417 |