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 | -2 |
| 2 | 0 |
| 3 | -8 |
| 4 | 12 |
| 5 | 8 |
| 6 | 0 |
| 7 | -128 |
| 8 | 252 |
| 9 | 472 |
| 10 | 840 |
| 11 | 1120 |
| 12 | 2112 |
| 13 | 128 |
| 14 | 0 |
| 15 | -32768 |
| 16 | 65532 |
| 17 | 131000 |
| 18 | 261528 |
| 19 | 519648 |
| 20 | 1029192 |
| 21 | 1991728 |
| 22 | 3865664 |
| 23 | 6825984 |
| 24 | 13835328 |
| 25 | 21056128 |
| 26 | 39611520 |
| 27 | 20680192 |
| 28 | 134234112 |
| 29 | 32768 |
| 30 | 0 |
| 31 | -2147483648 |
| 32 | 4294967292 |
| 33 | 8589934456 |
| 34 | 17179866936 |
| 35 | 34359709664 |
| 36 | 68719241112 |
| 37 | 137436945552 |