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 | 0 |
| 3 | -3 |
| 4 | -6 |
| 5 | 2 |
| 6 | 38 |
| 7 | 77 |
| 8 | -58 |
| 9 | -658 |
| 10 | -1240 |
| 11 | 1562 |
| 12 | 13064 |
| 13 | 22076 |
| 14 | -41710 |
| 15 | -279427 |
| 16 | -411418 |
| 17 | 1114998 |
| 18 | 6252048 |
| 19 | 7758726 |
| 20 | -29876900 |
| 21 | -143956676 |
| 22 | -143561972 |
| 23 | 802102322 |
| 24 | 3376515404 |
| 25 | 2496314012 |
| 26 | -21558225312 |
| 27 | -80113377828 |
| 28 | -37101814188 |
| 29 | 579611761168 |