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 | 1 |
| 2 | 5 |
| 3 | 27 |
| 4 | 252 |
| 5 | 2369 |
| 6 | 36103 |
| 7 | 518000 |
| 8 | 9756177 |
| 9 | 200951191 |
| 10 | 4899768134 |
| 11 | 113249415026 |
| 12 | 3553351288210 |
| 13 | 105127854228522 |
| 14 | 3433390910771142 |
| 15 | 122658122808278570 |
| 16 | 4957371400718135098 |
| 17 | 191264018429152335168 |
| 18 | 8676487463037943766552 |
| 19 | 377433133681960165450048 |
| 20 | 18780210971968950831128080 |