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 | 1 |
| 2 | 5 |
| 3 | 31 |
| 4 | 241 |
| 5 | 2261 |
| 6 | 24781 |
| 7 | 309835 |
| 8 | 4342241 |
| 9 | 67308841 |
| 10 | 1141960501 |
| 11 | 21026890391 |
| 12 | 417264626065 |
| 13 | 8871853115581 |
| 14 | 201100863674621 |
| 15 | 4838817223845571 |
| 16 | 123128720142540481 |
| 17 | 3302478863343928145 |
| 18 | 93091427773284348901 |
| 19 | 2750635764338982054031 |
| 20 | 84994418675445218025521 |