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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 23 |
| 4 | 103 |
| 5 | 455 |
| 6 | 1993 |
| 7 | 8679 |
| 8 | 37633 |
| 9 | 162643 |
| 10 | 701075 |
| 11 | 3015563 |
| 12 | 12948083 |
| 13 | 55513327 |
| 14 | 237705547 |
| 15 | 1016736115 |
| 16 | 4344766607 |
| 17 | 18550920063 |
| 18 | 79149527249 |
| 19 | 337482635279 |
| 20 | 1438155203665 |
| 21 | 6125448713739 |
| 22 | 26077796587441 |
| 23 | 110974892937943 |
| 24 | 472081467302933 |
| 25 | 2007534192877275 |
| 26 | 8534465842495133 |