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 | 7 |
| 4 | 1 |
| 5 | -1 |
| 6 | 11 |
| 7 | -1 |
| 8 | 319 |
| 9 | -143 |
| 10 | 715 |
| 11 | 1 |
| 12 | -26 |
| 13 | 559 |
| 14 | -221 |
| 15 | 4199 |
| 16 | -2 |
| 17 | 139 |
| 18 | -323 |
| 19 | 6137 |
| 20 | -2261 |
| 21 | 52003 |
| 22 | 1 |
| 23 | -10897 |
| 24 | 135983 |
| 25 | -4199 |
| 26 | 527459 |
| 27 | -52003 |
| 28 | 37145 |
| 29 | -1 |
| 30 | 15409 |
| 31 | -317281 |
| 32 | 21586489 |
| 33 | -52877 |
| 34 | 7429 |
| 35 | -88711 |
| 36 | 1964315 |
| 37 | 1 |
| 38 | -76 |
| 39 | 269123 |
| 40 | -100901 |
| 41 | 274873 |
| 42 | -8671 |
| 43 | 227447 |
| 44 | -227447 |
| 45 | 39803225 |
| 46 | -2 |
| 47 | 466003 |
| 48 | -213739 |
| 49 | 522629 |
| 50 | -59074189 |
| 51 | 226061641 |
| 52 | -10690009 |
| 53 | 25701511 |
| 54 | -42077695 |
| 55 | 547010035 |