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 | 0 |
| 4 | -1 |
| 5 | -1 |
| 6 | -1 |
| 7 | 2 |
| 8 | 6 |
| 9 | 11 |
| 10 | 5 |
| 11 | -21 |
| 12 | -78 |
| 13 | -124 |
| 14 | -53 |
| 15 | 335 |
| 16 | 1096 |
| 17 | 1727 |
| 18 | 441 |
| 19 | -5545 |
| 20 | -17196 |
| 21 | -25596 |
| 22 | -2251 |
| 23 | 97822 |
| 24 | 284072 |
| 25 | 399346 |
| 26 | -44721 |
| 27 | -1782873 |
| 28 | -4876069 |
| 29 | -6411063 |
| 30 | 2201418 |
| 31 | 33297536 |
| 32 | 85893931 |
| 33 | 104783903 |
| 34 | -64745927 |
| 35 | -632601621 |
| 36 | -1541899544 |
| 37 | -1727700472 |
| 38 | 1642436289 |
| 39 | 12171894474 |
| 40 | 28062518974 |