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 | 1 |
| 4 | 11 |
| 5 | 81 |
| 6 | 500 |
| 7 | 2794 |
| 8 | 14649 |
| 9 | 73489 |
| 10 | 356960 |
| 11 | 1691790 |
| 12 | 7864950 |
| 13 | 36000186 |
| 14 | 162697176 |
| 15 | 727505972 |
| 16 | 3223913365 |
| 17 | 14176874193 |
| 18 | 61926666824 |
| 19 | 268931341414 |
| 20 | 1161913686618 |
| 21 | 4997204887550 |
| 22 | 21404922261112 |
| 23 | 91351116184716 |
| 24 | 388581750349946 |
| 25 | 1647982988377786 |