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 | 3 |
| 2 | 19 |
| 3 | 141 |
| 4 | 1107 |
| 5 | 8953 |
| 6 | 73789 |
| 7 | 616227 |
| 8 | 5196627 |
| 9 | 44152809 |
| 10 | 377379369 |
| 11 | 3241135527 |
| 12 | 27948336381 |
| 13 | 241813226151 |
| 14 | 2098240353907 |
| 15 | 18252025766941 |
| 16 | 159114492071763 |
| 17 | 1389754816243449 |
| 18 | 12159131877715993 |
| 19 | 106542797484006471 |
| 20 | 934837217271732457 |
| 21 | 8212609533895771131 |