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 | 4 |
| 4 | 19 |
| 5 | 94 |
| 6 | 519 |
| 7 | 3144 |
| 8 | 20903 |
| 9 | 151418 |
| 10 | 1188947 |
| 11 | 10064924 |
| 12 | 91426347 |
| 13 | 887296422 |
| 14 | 9164847535 |
| 15 | 100398851344 |
| 16 | 1162831155151 |
| 17 | 14198949045106 |
| 18 | 182317628906283 |
| 19 | 2455925711626404 |
| 20 | 34632584722468115 |
| 21 | 510251350142181470 |
| 22 | 7840215226100517191 |
| 23 | 125427339735162102104 |