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 | 4 |
| 2 | 18 |
| 3 | 97 |
| 4 | 570 |
| 5 | 3489 |
| 6 | 21810 |
| 7 | 138044 |
| 8 | 881098 |
| 9 | 5658793 |
| 10 | 36520068 |
| 11 | 236619717 |
| 12 | 1538134272 |
| 13 | 10026366588 |
| 14 | 65513185896 |
| 15 | 428957025672 |