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 | 1 |
| 5 | -5 |
| 6 | -5 |
| 7 | 1 |
| 8 | -15 |
| 9 | 0 |
| 10 | -175 |
| 11 | 1 |
| 12 | -35 |
| 13 | 175 |
| 14 | -1225 |
| 15 | -12250 |
| 16 | 6125 |
| 17 | 1 |
| 18 | -70 |
| 19 | 1155 |
| 20 | -9800 |
| 21 | -67375 |
| 22 | -1414875 |
| 23 | 4716250 |
| 24 | 2358125 |
| 25 | 1 |
| 26 | -126 |
| 27 | 4725 |
| 28 | -80850 |
| 29 | 242550 |
| 30 | -12733875 |
| 31 | -202327125 |
| 32 | 3034906875 |
| 33 | 0 |
| 34 | 11802415625 |
| 35 | 1 |
| 36 | -210 |
| 37 | 15015 |
| 38 | -512050 |
| 39 | 7882875 |
| 40 | -121396275 |
| 41 | -1618617000 |
| 42 | -24886236375 |
| 43 | 1933235679375 |
| 44 | -6750981737500 |
| 45 | 35442654121875 |
| 46 | 177213270609375 |
| 47 | -59071090203125 |