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 | 5 |
| 5 | 31 |
| 6 | 153 |
| 7 | 778 |
| 8 | 3890 |
| 9 | 20693 |
| 10 | 114733 |
| 11 | 676347 |
| 12 | 4207203 |
| 13 | 27633048 |
| 14 | 190864320 |
| 15 | 1382896511 |
| 16 | 10479940137 |
| 17 | 82864510321 |
| 18 | 682075572641 |
| 19 | 5832740001550 |
| 20 | 51724150291262 |
| 21 | 474869801907015 |
| 22 | 4506715684635739 |
| 23 | 44152005758171637 |
| 24 | 445958868912515927 |
| 25 | 4638590331538888532 |