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 | 7 |
| 3 | 25 |
| 4 | 107 |
| 5 | 381 |
| 6 | 1589 |
| 7 | 5153 |
| 8 | 18809 |
| 9 | 68813 |
| 10 | 256859 |
| 11 | 883247 |
| 12 | 4997167 |
| 13 | 12448095 |
| 14 | 76804553 |
| 15 | 181129817 |
| 16 | 522024177 |
| 17 | 1884097881 |
| 18 | 16163873397 |
| 19 | 38888615377 |
| 20 | 239811969005 |