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 | -7 |
| 3 | -6 |
| 4 | -15 |
| 5 | -60 |
| 6 | -31 |
| 7 | -390 |
| 8 | -120 |
| 9 | -63 |
| 10 | -2100 |
| 11 | -2520 |
| 12 | -127 |
| 13 | -10206 |
| 14 | -31920 |
| 15 | -5040 |
| 16 | -255 |
| 17 | -46620 |
| 18 | -317520 |
| 19 | -181440 |
| 20 | -511 |
| 21 | -204630 |
| 22 | -2739240 |
| 23 | -3780000 |
| 24 | -362880 |
| 25 | -1023 |
| 26 | -874500 |
| 27 | -21538440 |
| 28 | -59875200 |
| 29 | -19958400 |
| 30 | -2047 |