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 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | 3 |
| 4 | 14 |
| 5 | 35 |
| 6 | 155 |
| 7 | 371 |
| 8 | 1518 |
| 9 | 3891 |
| 10 | 15745 |
| 11 | 40755 |
| 12 | 161459 |
| 13 | 426803 |
| 14 | 1671175 |
| 15 | 4469555 |
| 16 | 17301630 |
| 17 | 46805811 |
| 18 | 179569163 |
| 19 | 490156851 |
| 20 | 1865624365 |
| 21 | 5132989235 |
| 22 | 19404565567 |
| 23 | 53753361203 |
| 24 | 201986220339 |
| 25 | 562912506675 |
| 26 | 2103942223775 |
| 27 | 5894896300851 |
| 28 | 21927151270703 |
| 29 | 61732155503411 |