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 | 3 |
| 3 | -1 |
| 4 | 13 |
| 5 | -3 |
| 6 | 15 |
| 7 | -23 |
| 8 | 83 |
| 9 | -15 |
| 10 | 195 |
| 11 | -235 |
| 12 | 415 |
| 13 | -345 |
| 14 | 105 |
| 15 | -199 |
| 16 | 619 |
| 17 | -105 |
| 18 | 6225 |
| 19 | -6505 |
| 20 | 20005 |
| 21 | -17625 |
| 22 | 6825 |
| 23 | -9373 |
| 24 | 15673 |
| 25 | -12075 |
| 26 | 43575 |
| 27 | -46865 |
| 28 | 21665 |
| 29 | -20895 |
| 30 | 1155 |
| 31 | -2297 |
| 32 | 6917 |
| 33 | -1155 |
| 34 | 324975 |
| 35 | -328055 |
| 36 | 3541055 |
| 37 | -3415125 |
| 38 | 1525125 |
| 39 | -1652903 |
| 40 | 4960403 |
| 41 | -4318125 |
| 42 | 52513125 |
| 43 | -53137385 |
| 44 | 24787385 |
| 45 | -24604125 |
| 46 | 525525 |
| 47 | -727507 |
| 48 | 1212607 |
| 49 | -929775 |
| 50 | 57598275 |