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) |
|---|---|
| 1 | 0 |
| 2 | 3 |
| 3 | 16 |
| 4 | 57 |
| 5 | 192 |
| 6 | 599 |
| 7 | 1872 |
| 8 | 5727 |
| 9 | 17488 |
| 10 | 53115 |
| 11 | 161040 |
| 12 | 487073 |
| 13 | 1471680 |
| 14 | 4441167 |
| 15 | 13392272 |
| 16 | 40355877 |
| 17 | 121543680 |
| 18 | 365895947 |
| 19 | 1101089808 |
| 20 | 3312442185 |
| 21 | 9962240928 |
| 22 | 29954639751 |
| 23 | 90049997136 |
| 24 | 270661616363 |
| 25 | 813397065024 |
| 26 | 2444101696683 |
| 27 | 7343167947040 |
| 28 | 22059763982001 |
| 29 | 66263812628160 |