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 | -3 |
| 2 | 0 |
| 3 | 8 |
| 4 | -9 |
| 5 | 0 |
| 6 | 17 |
| 7 | -27 |
| 8 | 0 |
| 9 | 46 |
| 10 | -57 |
| 11 | 0 |
| 12 | 98 |
| 13 | -126 |
| 14 | 0 |
| 15 | 198 |
| 16 | -243 |
| 17 | 0 |
| 18 | 371 |
| 19 | -465 |
| 20 | 0 |
| 21 | 692 |
| 22 | -828 |
| 23 | 0 |
| 24 | 1205 |
| 25 | -1458 |
| 26 | 0 |
| 27 | 2082 |
| 28 | -2463 |
| 29 | 0 |
| 30 | 3463 |
| 31 | -4104 |
| 32 | 0 |
| 33 | 5678 |
| 34 | -6642 |
| 35 | 0 |
| 36 | 9085 |
| 37 | -10623 |
| 38 | 0 |
| 39 | 14370 |
| 40 | -16632 |
| 41 | 0 |
| 42 | 22273 |
| 43 | -25758 |
| 44 | 0 |
| 45 | 34178 |
| 46 | -39246 |
| 47 | 0 |
| 48 | 51674 |
| 49 | -59220 |
| 50 | 0 |
| 51 | 77362 |