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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 0 |
| 5 | -2 |
| 6 | -5 |
| 7 | -9 |
| 8 | -12 |
| 9 | -10 |
| 10 | 3 |
| 11 | 35 |
| 12 | 91 |
| 13 | 163 |
| 14 | 215 |
| 15 | 163 |
| 16 | -136 |
| 17 | -858 |
| 18 | -2107 |
| 19 | -3675 |
| 20 | -4639 |
| 21 | -2879 |
| 22 | 5161 |
| 23 | 23741 |
| 24 | 54910 |
| 25 | 91988 |
| 26 | 108843 |
| 27 | 47483 |
| 28 | -186582 |
| 29 | -700420 |
| 30 | -1527461 |
| 31 | -2440985 |
| 32 | -2656442 |
| 33 | -507076 |
| 34 | 6617735 |
| 35 | 21456279 |
| 36 | 44213835 |
| 37 | 67037683 |
| 38 | 65541879 |
| 39 | -9699085 |
| 40 | -232548686 |