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 | 4 |
| 1 | 22 |
| 2 | 128 |
| 3 | 746 |
| 4 | 4348 |
| 5 | 25342 |
| 6 | 147704 |
| 7 | 860882 |
| 8 | 5017588 |
| 9 | 29244646 |
| 10 | 170450288 |
| 11 | 993457082 |
| 12 | 5790292204 |
| 13 | 33748296142 |
| 14 | 196699484648 |
| 15 | 1146448611746 |
| 16 | 6681992185828 |
| 17 | 38945504503222 |
| 18 | 226991034833504 |
| 19 | 1323000704497802 |
| 20 | 7711013192153308 |
| 21 | 44943078448422046 |