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 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 26 |
| 6 | 105 |
| 7 | 444 |
| 8 | 1944 |
| 9 | 8734 |
| 10 | 40040 |
| 11 | 186550 |
| 12 | 880750 |
| 13 | 4204508 |
| 14 | 20260498 |
| 15 | 98419392 |
| 16 | 481442805 |
| 17 | 2369551218 |
| 18 | 11725590555 |
| 19 | 58303117680 |
| 20 | 291151523355 |
| 21 | 1459590130350 |
| 22 | 7342906908645 |
| 23 | 37058911816680 |
| 24 | 187579329483780 |
| 25 | 952006706210196 |
| 26 | 4843566974043900 |