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 | -10 |
| 3 | -21 |
| 4 | 89 |
| 5 | 320 |
| 6 | -659 |
| 7 | -4179 |
| 8 | 3070 |
| 9 | 49039 |
| 10 | 15269 |
| 11 | -524160 |
| 12 | -692119 |
| 13 | 5073641 |
| 14 | 12686950 |
| 15 | -43123101 |
| 16 | -182679551 |
| 17 | 291674560 |
| 18 | 2301149621 |
| 19 | -907270539 |
| 20 | -26219916370 |
| 21 | -16239940441 |
| 22 | 272179139629 |
| 23 | 450818484480 |
| 24 | -2543152051439 |