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 | 0 |
| 2 | 0 |
| 3 | -1 |
| 4 | -2 |
| 5 | -5 |
| 6 | -6 |
| 7 | -12 |
| 8 | -20 |
| 9 | -30 |
| 10 | -37 |
| 11 | -41 |
| 12 | -39 |
| 13 | -37 |
| 14 | -51 |
| 15 | -141 |
| 16 | -459 |
| 17 | -1355 |
| 18 | -3521 |
| 19 | -8212 |
| 20 | -17510 |
| 21 | -34685 |
| 22 | -64692 |
| 23 | -114953 |
| 24 | -196617 |
| 25 | -326254 |
| 26 | -527227 |
| 27 | -828432 |
| 28 | -1254932 |
| 29 | -1800115 |
| 30 | -2361626 |
| 31 | -2613748 |
| 32 | -1777205 |
| 33 | 1765725 |
| 34 | 11078200 |
| 35 | 31587185 |
| 36 | 72445272 |
| 37 | 148564309 |
| 38 | 283768148 |
| 39 | 516004565 |
| 40 | 906713910 |
| 41 | 1559424960 |
| 42 | 2660917133 |
| 43 | 4581930804 |
| 44 | 8140743021 |
| 45 | 15311144248 |
| 46 | 31111188060 |
| 47 | 68512065476 |