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 | 265 |
| 4 | 2733 |
| 5 | 25441 |
| 6 | 223461 |
| 7 | 1895545 |
| 8 | 15736413 |
| 9 | 128882641 |
| 10 | 1046542101 |
| 11 | 8451838825 |
| 12 | 68020609293 |
| 13 | 546227922241 |
| 14 | 4380272835141 |
| 15 | 35094966838105 |
| 16 | 281025802973373 |
| 17 | 2249545355064241 |
| 18 | 18003091856638581 |
| 19 | 144058517372685385 |
| 20 | 1152637601335180653 |