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) |
|---|---|
| 0 | 4 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 35 |
| 6 | 185 |
| 7 | 1155 |
| 8 | 8377 |
| 9 | 69106 |
| 10 | 639233 |
| 11 | 6552134 |
| 12 | 73711509 |
| 13 | 902965986 |
| 14 | 11964299312 |
| 15 | 170491265198 |
| 16 | 2599991794272 |
| 17 | 42249866656927 |
| 18 | 728810199831991 |
| 19 | 13300786146933842 |
| 20 | 256040133328476466 |