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 | 5 |
| 2 | 15 |
| 3 | 35 |
| 4 | 120 |
| 5 | 377 |
| 6 | 1505 |
| 7 | 5895 |
| 8 | 25395 |
| 9 | 110085 |
| 10 | 493131 |
| 11 | 2227275 |
| 12 | 10196680 |
| 13 | 46989185 |
| 14 | 218102685 |
| 15 | 1017448143 |
| 16 | 4768969770 |
| 17 | 22440372245 |
| 18 | 105966797755 |
| 19 | 501938733555 |
| 20 | 2384200683816 |
| 21 | 11353290089305 |