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 | 1 |
| 3 | 6 |
| 4 | 66 |
| 5 | 981 |
| 6 | 17576 |
| 7 | 359101 |
| 8 | 8109026 |
| 9 | 198480901 |
| 10 | 5197916551 |
| 11 | 144326504376 |
| 12 | 4220683214771 |
| 13 | 129349023338616 |
| 14 | 4138098976882836 |
| 15 | 137770738524681831 |
| 16 | 4761510500867829696 |
| 17 | 170476220596490911691 |
| 18 | 6311806909067054474161 |
| 19 | 241301669599996597349506 |
| 20 | 9512867537981387958217696 |
| 21 | 386276838889195561353811321 |