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 | -2 |
| 2 | -4 |
| 3 | -2 |
| 4 | -6 |
| 5 | -6 |
| 6 | -56 |
| 7 | -158 |
| 8 | -612 |
| 9 | -2070 |
| 10 | -7228 |
| 11 | -25238 |
| 12 | -89646 |
| 13 | -319466 |
| 14 | -1150168 |
| 15 | -4164978 |
| 16 | -15177718 |
| 17 | -55592614 |
| 18 | -204617788 |
| 19 | -756314982 |
| 20 | -2806456898 |
| 21 | -10450497682 |
| 22 | -39040372248 |
| 23 | -146273912858 |
| 24 | -549533738952 |
| 25 | -2069680656234 |
| 26 | -7812908945556 |