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 | 7 |
| 2 | 34 |
| 3 | 150 |
| 4 | 628 |
| 5 | 2540 |
| 6 | 10024 |
| 7 | 38840 |
| 8 | 148368 |
| 9 | 560368 |
| 10 | 2096928 |
| 11 | 7786592 |
| 12 | 28726592 |
| 13 | 105390272 |
| 14 | 384788096 |
| 15 | 1398978432 |
| 16 | 5067403520 |
| 17 | 18294707968 |
| 18 | 65854095872 |
| 19 | 236421150208 |
| 20 | 846732997632 |
| 21 | 3025927678976 |
| 22 | 10792083499008 |
| 23 | 38420157773824 |
| 24 | 136547503083520 |
| 25 | 484546494459904 |
| 26 | 1716976084393984 |