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 | 1 |
| 2 | 3 |
| 3 | 19 |
| 4 | 133 |
| 5 | 2501 |
| 6 | 15631 |
| 7 | 705895 |
| 8 | 8389641 |
| 9 | 258280489 |
| 10 | 4000040011 |
| 11 | 259374246011 |
| 12 | 2972033984173 |
| 13 | 279577021469773 |
| 14 | 4762288684702095 |
| 15 | 233543408203327951 |
| 16 | 9223372037928525841 |
| 17 | 778579070010669895697 |
| 18 | 13115469358498302735067 |
| 19 | 1874292305362402347591139 |