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 | 2 |
| 2 | 18 |
| 3 | 128 |
| 4 | 1506 |
| 5 | 15552 |
| 6 | 266548 |
| 7 | 4194304 |
| 8 | 89452674 |
| 9 | 2010077696 |
| 10 | 52439799700 |
| 11 | 1486016741376 |
| 12 | 46761291772836 |
| 13 | 1587429546508288 |
| 14 | 58431605635691172 |
| 15 | 2305913377957871616 |
| 16 | 97342665226310447618 |
| 17 | 4371823119477393063936 |
| 18 | 208266120619720061526886 |