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 | 7 |
| 4 | 13 |
| 5 | 101 |
| 6 | 361 |
| 7 | 2269 |
| 8 | 18201 |
| 9 | 48817 |
| 10 | 1436401 |
| 11 | -2283269 |
| 12 | 157443397 |
| 13 | -826037939 |
| 14 | 21355181849 |
| 15 | -160556822999 |
| 16 | 3084325024561 |
| 17 | -22223879489055 |
| 18 | 291212769688417 |
| 19 | 2180748026158255 |
| 20 | -118745486165378819 |
| 21 | 4884619264768661461 |
| 22 | -140063412525642293687 |
| 23 | 4020051993317128467029 |