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 | 41 |
| 4 | 413 |
| 5 | 4641 |
| 6 | 55797 |
| 7 | 702297 |
| 8 | 9137549 |
| 9 | 121909457 |
| 10 | 1658755685 |
| 11 | 22929591433 |
| 12 | 321111942781 |
| 13 | 4546112358529 |
| 14 | 64958195967957 |
| 15 | 935566629270201 |
| 16 | 13567825195172973 |
| 17 | 197957440018622769 |
| 18 | 2903721563443327557 |
| 19 | 42796201522669935081 |
| 20 | 633443408407612143453 |