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 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 52 |
| 5 | 214 |
| 6 | 928 |
| 7 | 4141 |
| 8 | 18940 |
| 9 | 88258 |
| 10 | 417616 |
| 11 | 2001058 |
| 12 | 9690184 |
| 13 | 47348812 |
| 14 | 233158144 |
| 15 | 1155900541 |
| 16 | 5764510060 |
| 17 | 28898899594 |
| 18 | 145556001136 |
| 19 | 736206912982 |
| 20 | 3737768204344 |
| 21 | 19042072755124 |
| 22 | 97313398530496 |
| 23 | 498737257238482 |
| 24 | 2562773039735896 |
| 25 | 13200732624526804 |
| 26 | 68148459129343648 |