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 | 0 |
| 4 | 1 |
| 5 | 5 |
| 6 | 6 |
| 7 | 7 |
| 8 | 288 |
| 9 | 262 |
| 10 | 13702 |
| 11 | 69531 |
| 12 | 610567 |
| 13 | 5356091 |
| 14 | 51724960 |
| 15 | 521956086 |
| 16 | 5467658641 |
| 17 | 59931636545 |
| 18 | 690518644584 |
| 19 | 8100858045744 |
| 20 | 99142980567486 |
| 21 | 1246972499954475 |
| 22 | 16142015005905558 |
| 23 | 215722810653380845 |
| 24 | 2955759897694815985 |
| 25 | 41614888439136252691 |