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 | 1 |
| 2 | 5 |
| 3 | 13 |
| 4 | 49 |
| 5 | 131 |
| 6 | 545 |
| 7 | 1723 |
| 8 | 6809 |
| 9 | 24484 |
| 10 | 94445 |
| 11 | 352727 |
| 12 | 1366273 |
| 13 | 5200313 |
| 14 | 20135939 |
| 15 | 77571083 |
| 16 | 301034537 |
| 17 | 1166803127 |
| 18 | 4540794476 |
| 19 | 17672631919 |
| 20 | 68943346009 |
| 21 | 269129827042 |
| 22 | 1052178506615 |
| 23 | 4116715363823 |
| 24 | 16124644677569 |
| 25 | 63205303337656 |
| 26 | 247964681424725 |
| 27 | 973469783435197 |