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 | 9 |
| 3 | 37 |
| 4 | 153 |
| 5 | 951 |
| 6 | 5473 |
| 7 | 42729 |
| 8 | 353937 |
| 9 | 3455083 |
| 10 | 30071001 |
| 11 | 426685293 |
| 12 | 4707929449 |
| 13 | 59350096287 |
| 14 | 882391484913 |
| 15 | 15177204356401 |
| 16 | 205119866263713 |
| 17 | 4040196156574419 |
| 18 | 64262949875511337 |
| 19 | 1408785031894483893 |
| 20 | 29514546353782633401 |
| 21 | 593055713389216814983 |