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 | 3 |
| 3 | 15 |
| 4 | 121 |
| 5 | 1665 |
| 6 | 43883 |
| 7 | 2437423 |
| 8 | 289320049 |
| 9 | 71423435521 |
| 10 | 35912764315347 |
| 11 | 36427941634714575 |
| 12 | 74226534887938021609 |
| 13 | 303199273967377493113473 |
| 14 | 2480131664037469755458069819 |
| 15 | 40602053121132407513785975382767 |
| 16 | 1329877926764331449042460153768864481 |