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 | 7 |
| 4 | 32 |
| 5 | 121 |
| 6 | 412 |
| 7 | 1317 |
| 8 | 4048 |
| 9 | 12144 |
| 10 | 35904 |
| 11 | 105249 |
| 12 | 306968 |
| 13 | 892217 |
| 14 | 2585468 |
| 15 | 7468532 |
| 16 | 21500800 |
| 17 | 61688513 |
| 18 | 176477988 |
| 19 | 503906221 |
| 20 | 1438235592 |
| 21 | 4110846808 |
| 22 | 11789919200 |
| 23 | 33991337521 |
| 24 | 98657320240 |
| 25 | 288505634480 |
| 26 | 850146795840 |
| 27 | 2522918119392 |
| 28 | 7531922736384 |