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 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 6 |
| 6 | 18 |
| 7 | 111 |
| 8 | 839 |
| 9 | 11076 |
| 10 | 260327 |
| 11 | 11698115 |
| 12 | 1005829079 |
| 13 | 163985322983 |
| 14 | 50324128516939 |
| 15 | 29000032348355991 |
| 16 | 31395491269119883535 |
| 17 | 63967623226983806252862 |
| 18 | 245868096558697545918087280 |