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 | 4 |
| 2 | 52 |
| 3 | 1456 |
| 4 | 71344 |
| 5 | 5422144 |
| 6 | 591013696 |
| 7 | 87470027008 |
| 8 | 16881715212544 |
| 9 | 4119138511860736 |
| 10 | 1239860692070081536 |
| 11 | 451309291913509679104 |
| 12 | 195416923398549691052032 |
| 13 | 99271797086463243054432256 |
| 14 | 58471088483926850159060598784 |
| 15 | 39526455815134550707524964777984 |