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 | 21 |
| 2 | 441 |
| 3 | 2307 |
| 4 | 19909 |
| 5 | 137719 |
| 6 | 1048423 |
| 7 | 7666319 |
| 8 | 57113109 |
| 9 | 422082891 |
| 10 | 3130112351 |
| 11 | 23173976223 |
| 12 | 171676789835 |
| 13 | 1271417316909 |
| 14 | 9417475398607 |
| 15 | 69753625991829 |
| 16 | 516671332697659 |
| 17 | 3826965495103137 |
| 18 | 28346096345105751 |
| 19 | 209956452832167033 |