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 | 6 |
| 2 | 42 |
| 3 | 198 |
| 4 | 1068 |
| 5 | 5196 |
| 6 | 25902 |
| 7 | 125874 |
| 8 | 609780 |
| 9 | 2933562 |
| 10 | 14058132 |
| 11 | 67139772 |
| 12 | 319822572 |
| 13 | 1520161374 |
| 14 | 7211880744 |
| 15 | 34157352042 |
| 16 | 161541458514 |
| 17 | 763007236542 |
| 18 | 3599867690610 |