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 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 55 |
| 5 | 377 |
| 6 | 4291 |
| 7 | 60028 |
| 8 | 1058058 |
| 9 | 21552969 |
| 10 | 500280022 |
| 11 | 12969598086 |
| 12 | 371514016094 |
| 13 | 11649073935505 |
| 14 | 396857785692525 |
| 15 | 14596464294191704 |
| 16 | 576460770691256356 |
| 17 | 24330595997127372497 |
| 18 | 1092955780817066765469 |
| 19 | 52063675152021153895330 |
| 20 | 2621440000054016000176044 |