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 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 3 |
| 6 | 7 |
| 7 | 27 |
| 8 | 120 |
| 9 | 590 |
| 10 | 3172 |
| 11 | 18291 |
| 12 | 112597 |
| 13 | 731646 |
| 14 | 5002261 |
| 15 | 35805035 |
| 16 | 267427870 |
| 17 | 2077890719 |
| 18 | 16753007782 |
| 19 | 139843832074 |
| 20 | 1206213748404 |
| 21 | 10731971520412 |
| 22 | 98340872850392 |
| 23 | 926788397662602 |
| 24 | 8971598464914888 |
| 25 | 89105060389927172 |
| 26 | 907030917078092542 |