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 | 0 |
| 4 | 1 |
| 5 | 1 |
| 6 | 0 |
| 7 | 0 |
| 8 | 4 |
| 9 | 8 |
| 10 | 4 |
| 11 | 0 |
| 12 | 22 |
| 13 | 66 |
| 14 | 66 |
| 15 | 22 |
| 16 | 140 |
| 17 | 560 |
| 18 | 840 |
| 19 | 560 |
| 20 | 1109 |
| 21 | 4845 |
| 22 | 9690 |
| 23 | 9690 |
| 24 | 11929 |
| 25 | 43473 |
| 26 | 106260 |
| 27 | 141680 |
| 28 | 160080 |
| 29 | 419244 |
| 30 | 1137304 |
| 31 | 1883700 |
| 32 | 2304432 |
| 33 | 4496076 |
| 34 | 12157236 |
| 35 | 23614812 |
| 36 | 32813500 |
| 37 | 53821332 |
| 38 | 132821856 |
| 39 | 285795696 |
| 40 | 451409380 |