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 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 7 |
| 6 | 23 |
| 7 | 65 |
| 8 | 165 |
| 9 | 398 |
| 10 | 976 |
| 11 | 2618 |
| 12 | 7997 |
| 13 | 27205 |
| 14 | 97705 |
| 15 | 355631 |
| 16 | 1289746 |
| 17 | 4662069 |
| 18 | 16971775 |
| 19 | 63150385 |
| 20 | 243513801 |
| 21 | 980670052 |
| 22 | 4121324752 |
| 23 | 17941655332 |
| 24 | 80143362633 |
| 25 | 364476958473 |
| 26 | 1680382664145 |
| 27 | 7847729640629 |
| 28 | 37192941056498 |
| 29 | 179431901258459 |