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 | 11 |
| 3 | 81 |
| 4 | 611 |
| 5 | 4798 |
| 6 | 39320 |
| 7 | 333583 |
| 8 | 2897573 |
| 9 | 25632474 |
| 10 | 230231687 |
| 11 | 2091437006 |
| 12 | 19145032382 |
| 13 | 176258021378 |
| 14 | 1630867803755 |
| 15 | 15161044498785 |
| 16 | 141573907590908 |
| 17 | 1327916557473475 |
| 18 | 12513166293358138 |
| 19 | 118472791400037286 |
| 20 | 1126683083504083356 |
| 21 | 10754171449735292485 |