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 | 13 |
| 3 | 1027 |
| 4 | 52741 |
| 5 | 468481 |
| 6 | 2890927 |
| 7 | 4166539 |
| 8 | 37009999 |
| 9 | 228383233 |
| 10 | 999884119 |
| 11 | 1345997497 |
| 12 | 1900627417 |
| 13 | 2126334691 |
| 14 | 4499474941 |
| 15 | 5037873529 |
| 16 | 11728490839 |
| 17 | 104180336299 |
| 18 | 105897267463 |
| 19 | 150149565943 |
| 20 | 926550776281 |
| 21 | 4056529870783 |