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 | 0 |
| 3 | -3 |
| 4 | -5 |
| 5 | -16 |
| 6 | -39 |
| 7 | -105 |
| 8 | -272 |
| 9 | -715 |
| 10 | -1869 |
| 11 | -4896 |
| 12 | -12815 |
| 13 | -33553 |
| 14 | -87840 |
| 15 | -229971 |
| 16 | -602069 |
| 17 | -1576240 |
| 18 | -4126647 |
| 19 | -10803705 |
| 20 | -28284464 |
| 21 | -74049691 |
| 22 | -193864605 |
| 23 | -507544128 |
| 24 | -1328767775 |
| 25 | -3478759201 |
| 26 | -9107509824 |
| 27 | -23843770275 |
| 28 | -62423800997 |
| 29 | -163427632720 |