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 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | -2 |
| 6 | 2 |
| 7 | 2 |
| 8 | 9 |
| 9 | -6 |
| 10 | 6 |
| 11 | 9 |
| 12 | -28 |
| 13 | 12 |
| 14 | -24 |
| 15 | 24 |
| 16 | 44 |
| 17 | 185 |
| 18 | 100 |
| 19 | 60 |
| 20 | -120 |
| 21 | 120 |
| 22 | 265 |
| 23 | -846 |
| 24 | -690 |
| 25 | -120 |
| 26 | 360 |
| 27 | -720 |
| 28 | 720 |
| 29 | 1854 |
| 30 | 7777 |
| 31 | 2478 |
| 32 | 5250 |
| 33 | -840 |
| 34 | 2520 |
| 35 | -5040 |
| 36 | 5040 |
| 37 | 14833 |
| 38 | -47384 |
| 39 | 33656 |
| 40 | -40656 |
| 41 | 1680 |
| 42 | -6720 |
| 43 | 20160 |
| 44 | -40320 |
| 45 | 40320 |
| 46 | 133496 |
| 47 | 559953 |
| 48 | -347832 |
| 49 | 181944 |
| 50 | 359856 |
| 51 | 15120 |
| 52 | -60480 |
| 53 | 181440 |
| 54 | -362880 |
| 55 | 362880 |