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 | 1 |
| 1 | 3 |
| 2 | 11 |
| 3 | 45 |
| 4 | 191 |
| 5 | 813 |
| 6 | 3431 |
| 7 | 14325 |
| 8 | 59231 |
| 9 | 242973 |
| 10 | 990551 |
| 11 | 4019205 |
| 12 | 16249871 |
| 13 | 65522733 |
| 14 | 263668871 |
| 15 | 1059425685 |
| 16 | 4251986111 |
| 17 | 17050860093 |
| 18 | 68332318391 |
| 19 | 273716169765 |
| 20 | 1096025891951 |
| 21 | 4387588255053 |
| 22 | 17560809179111 |
| 23 | 70274609387445 |
| 24 | 281192563951391 |
| 25 | 1125052651787613 |