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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 2 |
| 7 | 11 |
| 8 | 65 |
| 9 | 433 |
| 10 | 3271 |
| 11 | 27741 |
| 12 | 261231 |
| 13 | 2708064 |
| 14 | 30671367 |
| 15 | 377034018 |
| 16 | 5001404982 |
| 17 | 71229862678 |
| 18 | 1084282429946 |
| 19 | 17571257417630 |
| 20 | 302064161086250 |
| 21 | 5490937395703435 |
| 22 | 105243824522368960 |
| 23 | 2121386876912041845 |
| 24 | 44863116021267642255 |
| 25 | 993272322666679219071 |
| 26 | 22977273619066571708457 |