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 | 4 |
| 4 | 13 |
| 5 | 41 |
| 6 | 136 |
| 7 | 505 |
| 8 | 2171 |
| 9 | 10693 |
| 10 | 58246 |
| 11 | 340242 |
| 12 | 2095435 |
| 13 | 13492077 |
| 14 | 90267633 |
| 15 | 623383765 |
| 16 | 4414350135 |
| 17 | 31899350954 |
| 18 | 235002008725 |
| 19 | 1773013299342 |
| 20 | 13855253098226 |
| 21 | 114135759054965 |
| 22 | 1010686200326760 |
| 23 | 9744658443894282 |
| 24 | 102153128291263124 |
| 25 | 1147158516520205256 |