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 | 45 |
| 4 | -2430 |
| 5 | 433026 |
| 6 | -245525742 |
| 7 | 434685788658 |
| 8 | -2376644549487615 |
| 9 | 39849199161258840705 |
| 10 | -2039314646436750180150939 |
| 11 | 317469566015078743658568283029 |
| 12 | -149970083228995077874358388356635368 |
| 13 | 214577598849654850870918566871719460091160 |