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 | 21 |
| 3 | 93 |
| 4 | 453 |
| 5 | 2121 |
| 6 | 9926 |
| 7 | 46776 |
| 8 | 220655 |
| 9 | 1041073 |
| 10 | 4909754 |
| 11 | 23155430 |
| 12 | 109215035 |
| 13 | 515130861 |
| 14 | 2429644852 |
| 15 | 11459531527 |
| 16 | 54049709552 |
| 17 | 254929619681 |
| 18 | 1202393496717 |
| 19 | 5671171946685 |
| 20 | 26748483522662 |
| 21 | 126161124832462 |
| 22 | 595047865009759 |