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) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | -1 |
| 4 | -4 |
| 5 | -11 |
| 6 | -24 |
| 7 | -57 |
| 8 | -112 |
| 9 | -243 |
| 10 | -480 |
| 11 | -1013 |
| 12 | -1964 |
| 13 | -4083 |
| 14 | -8064 |
| 15 | -16309 |
| 16 | -32496 |
| 17 | -65519 |
| 18 | -130440 |
| 19 | -262125 |
| 20 | -523156 |
| 21 | -1048263 |
| 22 | -2095104 |
| 23 | -4194281 |
| 24 | -8383760 |
| 25 | -16777015 |
| 26 | -33546240 |
| 27 | -67107609 |
| 28 | -134200860 |
| 29 | -268435427 |
| 30 | -536835096 |
| 31 | -1073741793 |
| 32 | -2147417216 |
| 33 | -4294962187 |
| 34 | -8589803520 |
| 35 | -17179867533 |
| 36 | -34359463812 |