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 | 5 |
| 2 | 17 |
| 3 | 143 |
| 4 | 355 |
| 5 | 4043 |
| 6 | 5177 |
| 7 | 367271 |
| 8 | 713723 |
| 9 | 2410003 |
| 10 | 109669391 |
| 11 | 85569361 |
| 12 | 11122330591 |
| 13 | 245535162239 |
| 14 | 52108328723 |
| 15 | 70514170732823 |
| 16 | 1753034045867 |
| 17 | 3087820148584967 |
| 18 | 3365163124738543 |
| 19 | 15216530369586809 |
| 20 | 9955926989110451149 |
| 21 | 63735241273696485041 |