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 | 1 |
| 2 | 121 |
| 3 | 553 |
| 4 | 2463 |
| 5 | 35733 |
| 6 | 263489 |
| 7 | 1810441 |
| 8 | 16855693 |
| 9 | 138016847 |
| 10 | 1087543621 |
| 11 | 9228070694 |
| 12 | 76704166206 |
| 13 | 628908321069 |
| 14 | 5245176224753 |
| 15 | 43644001864720 |
| 16 | 361707709471024 |
| 17 | 3008980635521615 |
| 18 | 25033019588307299 |
| 19 | 208047564104356544 |