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 | 2 |
| 3 | 7 |
| 4 | 20 |
| 5 | 70 |
| 6 | 234 |
| 7 | 832 |
| 8 | 2956 |
| 9 | 10759 |
| 10 | 39394 |
| 11 | 145892 |
| 12 | 543564 |
| 13 | 2038831 |
| 14 | 7684116 |
| 15 | 29092055 |
| 16 | 110550260 |
| 17 | 421495147 |
| 18 | 1611662256 |