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 | -3 |
| 3 | -8 |
| 4 | -21 |
| 5 | -56 |
| 6 | -154 |
| 7 | -440 |
| 8 | -1309 |
| 9 | -4048 |
| 10 | -12958 |
| 11 | -42712 |
| 12 | -144210 |
| 13 | -496432 |
| 14 | -1735764 |
| 15 | -6145968 |
| 16 | -21986781 |
| 17 | -79331232 |
| 18 | -288307254 |
| 19 | -1054253208 |
| 20 | -3875769606 |
| 21 | -14315659632 |
| 22 | -53097586284 |
| 23 | -197677736208 |
| 24 | -738415086066 |