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 | 2 |
| 2 | 18 |
| 3 | 56 |
| 4 | 238 |
| 5 | 902 |
| 6 | 3564 |
| 7 | 13862 |
| 8 | 54238 |
| 9 | 211736 |
| 10 | 827298 |
| 11 | 3231362 |
| 12 | 12623044 |
| 13 | 49308482 |
| 14 | 192613698 |
| 15 | 752401496 |
| 16 | 2939092798 |
| 17 | 11480914982 |
| 18 | 44847668844 |
| 19 | 175187526662 |
| 20 | 684331472398 |
| 21 | 2673190054136 |
| 22 | 10442227799538 |
| 23 | 40790261396162 |
| 24 | 159338166024964 |
| 25 | 622419427368002 |