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 | 1 |
| 3 | -1 |
| 4 | -4 |
| 5 | -5 |
| 6 | 6 |
| 7 | 36 |
| 8 | 46 |
| 9 | -101 |
| 10 | -515 |
| 11 | -506 |
| 12 | 2554 |
| 13 | 9991 |
| 14 | 3067 |
| 15 | -79915 |
| 16 | -227056 |
| 17 | 205681 |
| 18 | 2841708 |
| 19 | 5134140 |
| 20 | -18296153 |
| 21 | -107927240 |
| 22 | -66578269 |
| 23 | 1174691649 |
| 24 | 4059143386 |
| 25 | -4667894370 |
| 26 | -69377504739 |
| 27 | -126787267800 |
| 28 | 669710503012 |
| 29 | 3835079736835 |
| 30 | 475781902203 |