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 | 11 |
| 2 | 81 |
| 3 | 515 |
| 4 | 3121 |
| 5 | 16875 |
| 6 | 84769 |
| 7 | 394691 |
| 8 | 1733537 |
| 9 | 7129227 |
| 10 | 27634481 |
| 11 | 102386243 |
| 12 | 365127249 |
| 13 | 1256538091 |
| 14 | 4180101249 |
| 15 | 13457728387 |
| 16 | 41966634049 |
| 17 | 126929576971 |
| 18 | 373074639633 |
| 19 | 1067860637059 |
| 20 | 2981845163377 |
| 21 | 8133266915563 |