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 | 0 |
| 1 | 1 |
| 2 | 15 |
| 3 | 193 |
| 4 | 2479 |
| 5 | 33081 |
| 6 | 464807 |
| 7 | 6906257 |
| 8 | 108589887 |
| 9 | 1805179321 |
| 10 | 31676392519 |
| 11 | 585609896433 |
| 12 | 11383428770303 |
| 13 | 232204651095353 |
| 14 | 4961029124266599 |
| 15 | 110811507291845521 |
| 16 | 2583228239189752447 |
| 17 | 62748345739947178617 |
| 18 | 1585780756628964990407 |
| 19 | 41635723030339339863281 |