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 | -5 |
| 2 | 71 |
| 3 | -105 |
| 4 | 6487 |
| 5 | -1645 |
| 6 | 122441 |
| 7 | -19985 |
| 8 | 1049887 |
| 9 | -248661 |
| 10 | 25979005 |
| 11 | -2042425 |
| 12 | 11608085917 |
| 13 | -62770877 |
| 14 | 267788927 |
| 15 | 2703436575 |
| 16 | 234292680479 |
| 17 | -332582883493 |
| 18 | 3704188911107 |
| 19 | 45663269876215 |
| 20 | 15433397641757 |
| 21 | -7778087842877709 |
| 22 | 61723221856153 |
| 23 | 1595021223984687695 |