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 | -3 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | -4 |
| 6 | 10 |
| 7 | -20 |
| 8 | 36 |
| 9 | -64 |
| 10 | 120 |
| 11 | -239 |
| 12 | 484 |
| 13 | -946 |
| 14 | 1716 |
| 15 | -2794 |
| 16 | 3872 |
| 17 | -3872 |
| 18 | 1 |
| 19 | 14160 |
| 20 | -52478 |
| 21 | 143716 |
| 22 | -345400 |
| 23 | 767976 |
| 24 | -1613128 |
| 25 | 3226257 |
| 26 | -6148960 |
| 27 | 11119030 |
| 28 | -18874260 |
| 29 | 29414650 |
| 30 | -39955040 |
| 31 | 39955040 |
| 32 | 1 |
| 33 | -151615948 |
| 34 | 575723786 |
| 35 | -1611404740 |
| 36 | 3936821260 |