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 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | -3 |
| 7 | -7 |
| 8 | -3 |
| 9 | 5 |
| 10 | 25 |
| 11 | 45 |
| 12 | -3 |
| 13 | -107 |
| 14 | -191 |
| 15 | -175 |
| 16 | 253 |
| 17 | 1045 |
| 18 | 1189 |
| 19 | -171 |
| 20 | -3547 |
| 21 | -7527 |
| 22 | -4603 |
| 23 | 11497 |
| 24 | 33945 |
| 25 | 40869 |
| 26 | -10487 |
| 27 | -141071 |
| 28 | -248407 |
| 29 | -120131 |
| 30 | 421141 |
| 31 | 1227961 |
| 32 | 1332777 |
| 33 | -726439 |
| 34 | -5051271 |
| 35 | -8369959 |
| 36 | -3306635 |
| 37 | 16738977 |
| 38 | 43110597 |
| 39 | 41391949 |
| 40 | -33360335 |
| 41 | -183387403 |
| 42 | -283721435 |