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 | 11 |
| 4 | 48 |
| 5 | 244 |
| 6 | 1420 |
| 7 | 9318 |
| 8 | 68019 |
| 9 | 545984 |
| 10 | 4772890 |
| 11 | 45079020 |
| 12 | 456958589 |
| 13 | 4943710161 |
| 14 | 56809133108 |
| 15 | 690510011727 |
| 16 | 8845800877774 |
| 17 | 119052630071419 |
| 18 | 1678622651280617 |
| 19 | 24733730857289108 |
| 20 | 379989034049167269 |