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 | 11 |
| 2 | 79 |
| 3 | 575 |
| 4 | 4351 |
| 5 | 33791 |
| 6 | 266239 |
| 7 | 2113535 |
| 8 | 16842751 |
| 9 | 134479871 |
| 10 | 1074790399 |
| 11 | 8594128895 |
| 12 | 68736253951 |
| 13 | 549822922751 |
| 14 | 4398314946559 |
| 15 | 35185445830655 |
| 16 | 281479271677951 |
| 17 | 2251816993554431 |
| 18 | 18014467228958719 |
| 19 | 144115462953762815 |