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 | 3 |
| 2 | 15 |
| 3 | 93 |
| 4 | 458 |
| 5 | 2163 |
| 6 | 10789 |
| 7 | 53813 |
| 8 | 265397 |
| 9 | 1311447 |
| 10 | 6493700 |
| 11 | 32130833 |
| 12 | 158937397 |
| 13 | 786355013 |
| 14 | 3890673454 |
| 15 | 19249161646 |
| 16 | 95235762295 |
| 17 | 471186213619 |
| 18 | 2331226488364 |
| 19 | 11533889645847 |
| 20 | 57064690337149 |
| 21 | 282331462742945 |
| 22 | 1396854097460108 |