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 | 15 |
| 3 | 683 |
| 4 | 61332 |
| 5 | 9135004 |
| 6 | 2035708760 |
| 7 | 634172615600 |
| 8 | 263166948202080 |
| 9 | 140322186951905736 |
| 10 | 93484350581344936344 |
| 11 | 76095870609142447018152 |
| 12 | 74311960997497053384537408 |
| 13 | 85748280952260853814490688656 |