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 | 1 |
| 2 | 1 |
| 3 | 16 |
| 4 | 61 |
| 5 | 676 |
| 6 | 5701 |
| 7 | 60376 |
| 8 | 798841 |
| 9 | 9635536 |
| 10 | 160878601 |
| 11 | 2367914176 |
| 12 | 44902245301 |
| 13 | 807083463616 |
| 14 | 16799688310861 |
| 15 | 358223448539776 |
| 16 | 8158048770370801 |
| 17 | 199405713714155776 |
| 18 | 4987832102850957841 |
| 19 | 135848995301247809536 |
| 20 | 3737769145322321702701 |