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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 12 |
| 6 | 33 |
| 7 | 76 |
| 8 | 210 |
| 9 | 520 |
| 10 | 1410 |
| 11 | 3590 |
| 12 | 9618 |
| 13 | 24920 |
| 14 | 66521 |
| 15 | 174412 |
| 16 | 465264 |
| 17 | 1229184 |
| 18 | 3280458 |
| 19 | 8710668 |
| 20 | 23271116 |
| 21 | 62014876 |
| 22 | 165888184 |
| 23 | 443255164 |
| 24 | 1187255082 |
| 25 | 3178905184 |
| 26 | 8525398102 |
| 27 | 22864654046 |
| 28 | 61391533270 |
| 29 | 164872981784 |