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 | 2 |
| 2 | 66 |
| 3 | 1212 |
| 4 | 15620 |
| 5 | 155850 |
| 6 | 1272810 |
| 7 | 8823080 |
| 8 | 53265960 |
| 9 | 285510150 |
| 10 | 1379301990 |
| 11 | 6078578508 |
| 12 | 24680519604 |
| 13 | 93093230958 |
| 14 | 328512273390 |
| 15 | 1091144804400 |
| 16 | 3429182092560 |
| 17 | 10244035242630 |
| 18 | 29206656395910 |
| 19 | 79759293448100 |