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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 26 |
| 6 | 91 |
| 7 | 246 |
| 8 | 2801 |
| 9 | 26650 |
| 10 | 159601 |
| 11 | 702406 |
| 12 | 12479941 |
| 13 | 172561676 |
| 14 | 1462655195 |
| 15 | 8918930476 |
| 16 | 215370384321 |
| 17 | 3906667179836 |
| 18 | 42828875064001 |
| 19 | 333816101642140 |
| 20 | 10190496077676901 |
| 21 | 228789539391769336 |
| 22 | 3077152545301687931 |
| 23 | 29203537040556576776 |