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 | 27 |
| 4 | 768 |
| 5 | 8771 |
| 6 | 63468 |
| 7 | 340620 |
| 8 | 1470784 |
| 9 | 5371002 |
| 10 | 17153352 |
| 11 | 49075521 |
| 12 | 128066400 |
| 13 | 309124101 |
| 14 | 697874996 |
| 15 | 1486830618 |
| 16 | 3011414784 |
| 17 | 5833686340 |
| 18 | 10863883728 |
| 19 | 19532496375 |
| 20 | 34028554944 |
| 21 | 57623258007 |
| 22 | 95101946940 |
| 23 | 153331834040 |
| 24 | 241997811264 |
| 25 | 374544148830 |
| 26 | 569365964440 |
| 27 | 851301035325 |
| 28 | 1253479866912 |
| 29 | 1819599953913 |
| 30 | 2606698902276 |