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 | 3 |
| 2 | 15 |
| 3 | 103 |
| 4 | 879 |
| 5 | 8787 |
| 6 | 99061 |
| 7 | 1227369 |
| 8 | 16409937 |
| 9 | 233588249 |
| 10 | 3504149013 |
| 11 | 54963273921 |
| 12 | 895797910129 |
| 13 | 15094359120933 |
| 14 | 261882874511985 |
| 15 | 4662472442136561 |
| 16 | 84940003965749601 |
| 17 | 1579633610378515989 |
| 18 | 29927014639635474589 |
| 19 | 576597813697577550447 |
| 20 | 11280469732919709557493 |