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 | 21 |
| 2 | 169 |
| 3 | 1101 |
| 4 | 8369 |
| 5 | 64671 |
| 6 | 511957 |
| 7 | 4108671 |
| 8 | 33331889 |
| 9 | 272616609 |
| 10 | 2244091579 |
| 11 | 18568201871 |
| 12 | 154285123493 |
| 13 | 1286408940149 |
| 14 | 10756655080753 |
| 15 | 90159207784161 |
| 16 | 757192897525073 |
| 17 | 6369787770505701 |
| 18 | 53659598197631131 |
| 19 | 452559057596166759 |