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 | -6 |
| 2 | 9 |
| 3 | -2 |
| 4 | 0 |
| 5 | 0 |
| 6 | -1 |
| 7 | -6 |
| 8 | -27 |
| 9 | -110 |
| 10 | -429 |
| 11 | -1638 |
| 12 | -6188 |
| 13 | -23256 |
| 14 | -87210 |
| 15 | -326876 |
| 16 | -1225785 |
| 17 | -4601610 |
| 18 | -17298645 |
| 19 | -65132550 |
| 20 | -245642760 |
| 21 | -927983760 |
| 22 | -3511574910 |
| 23 | -13309856820 |
| 24 | -50528160150 |
| 25 | -192113383644 |
| 26 | -731508653106 |
| 27 | -2789279908316 |
| 28 | -10649977831752 |
| 29 | -40715807302800 |