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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 15 |
| 6 | 49 |
| 7 | 160 |
| 8 | 498 |
| 9 | 1544 |
| 10 | 4715 |
| 11 | 14356 |
| 12 | 43420 |
| 13 | 131145 |
| 14 | 394990 |
| 15 | 1188564 |
| 16 | 3572400 |
| 17 | 10732065 |
| 18 | 32224216 |
| 19 | 96733636 |
| 20 | 290317660 |
| 21 | 871200664 |
| 22 | 2614083394 |
| 23 | 7843255300 |
| 24 | 23531731530 |
| 25 | 70599259170 |
| 26 | 211805771345 |