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 | 1 |
| 2 | 6 |
| 3 | 40 |
| 4 | 232 |
| 5 | 1352 |
| 6 | 7854 |
| 7 | 45683 |
| 8 | 266214 |
| 9 | 1554684 |
| 10 | 9098740 |
| 11 | 53357985 |
| 12 | 313495934 |
| 13 | 1845063496 |
| 14 | 10876094870 |
| 15 | 64203285600 |
| 16 | 379498497900 |
| 17 | 2245861126596 |
| 18 | 13305537121404 |
| 19 | 78907795361228 |
| 20 | 468393492593496 |