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 | -2 |
| 3 | 2 |
| 4 | -1 |
| 5 | -2 |
| 6 | 10 |
| 7 | -30 |
| 8 | 76 |
| 9 | -173 |
| 10 | 363 |
| 11 | -717 |
| 12 | 1363 |
| 13 | -2551 |
| 14 | 4797 |
| 15 | -9189 |
| 16 | 18015 |
| 17 | -36008 |
| 18 | 72725 |
| 19 | -146930 |
| 20 | 294423 |
| 21 | -581758 |
| 22 | 1130231 |
| 23 | -2158552 |
| 24 | 4061201 |
| 25 | -7557522 |
| 26 | 13983585 |
| 27 | -25872679 |
| 28 | 48115364 |
| 29 | -90273986 |
| 30 | 171186911 |
| 31 | -328120527 |
| 32 | 635014942 |
| 33 | -1239093092 |
| 34 | 2434924044 |