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 | 4 |
| 2 | -866 |
| 3 | -10520 |
| 4 | 2249356 |
| 5 | 46111984 |
| 6 | -9735212024 |
| 7 | -282965467424 |
| 8 | 58973337166480 |
| 9 | 2232497686809664 |
| 10 | -459200359680279584 |
| 11 | -21527431036382354816 |
| 12 | 4369052165472543104704 |
| 13 | 245322538750961015791360 |
| 14 | -49114261974304335175370624 |
| 15 | -3225699756394083963693195776 |