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 | 3 |
| 1 | 11 |
| 2 | 39 |
| 3 | 143 |
| 4 | 543 |
| 5 | 2111 |
| 6 | 8319 |
| 7 | 33023 |
| 8 | 131583 |
| 9 | 525311 |
| 10 | 2099199 |
| 11 | 8392703 |
| 12 | 33562623 |
| 13 | 134234111 |
| 14 | 536903679 |
| 15 | 2147549183 |
| 16 | 8590065663 |
| 17 | 34360000511 |
| 18 | 137439477759 |
| 19 | 549756862463 |
| 20 | 2199025352703 |
| 21 | 8796097216511 |
| 22 | 35184380477439 |
| 23 | 140737505132543 |
| 24 | 562949986975743 |