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 | 3 |
| 3 | 12 |
| 4 | 48 |
| 5 | 197 |
| 6 | 815 |
| 7 | 3391 |
| 8 | 14153 |
| 9 | 59185 |
| 10 | 247791 |
| 11 | 1038186 |
| 12 | 4351706 |
| 13 | 18245861 |
| 14 | 76514483 |
| 15 | 320899470 |
| 16 | 1345931153 |
| 17 | 5645394769 |
| 18 | 23679726926 |
| 19 | 99326654214 |
| 20 | 416638208001 |
| 21 | 1747652017025 |
| 22 | 7330817809523 |
| 23 | 30750407615699 |
| 24 | 128988186902345 |
| 25 | 541064919671773 |
| 26 | 2269598571509748 |
| 27 | 9520261251293028 |