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) |
|---|---|
| 2 | 1 |
| 3 | 7 |
| 4 | 37 |
| 5 | 178 |
| 6 | 825 |
| 7 | 3774 |
| 8 | 17250 |
| 9 | 79326 |
| 10 | 368516 |
| 11 | 1733597 |
| 12 | 8268603 |
| 13 | 40003178 |
| 14 | 196273837 |
| 15 | 976066486 |
| 16 | 4915503146 |
| 17 | 25042730042 |
| 18 | 128927697340 |
| 19 | 670023585820 |
| 20 | 3511276691660 |
| 21 | 18537816521102 |
| 22 | 98514404946264 |
| 23 | 526575421631986 |