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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 14 |
| 8 | 105 |
| 9 | 560 |
| 10 | 2380 |
| 11 | 8568 |
| 12 | 27132 |
| 13 | 77521 |
| 14 | 203518 |
| 15 | 497826 |
| 16 | 1148126 |
| 17 | 2527609 |
| 18 | 5401676 |
| 19 | 11508168 |
| 20 | 25437917 |
| 21 | 60978022 |
| 22 | 162008098 |
| 23 | 468103230 |
| 24 | 1409724358 |
| 25 | 4259541790 |
| 26 | 12617126893 |
| 27 | 36241765553 |
| 28 | 100599743538 |
| 29 | 269998374114 |
| 30 | 702694008002 |