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 | 11 |
| 4 | 81 |
| 5 | 381 |
| 6 | 1673 |
| 7 | 8338 |
| 8 | 43585 |
| 9 | 220037 |
| 10 | 1086581 |
| 11 | 5401793 |
| 12 | 27090649 |
| 13 | 135792879 |
| 14 | 678626796 |
| 15 | 3389980516 |
| 16 | 16949548097 |
| 17 | 84773530931 |
| 18 | 423896384077 |
| 19 | 2119296824851 |
| 20 | 10596060837121 |
| 21 | 52981415499506 |
| 22 | 264911698225527 |
| 23 | 1324553898108366 |
| 24 | 6622726587716561 |
| 25 | 33113628115834381 |
| 26 | 165568491457714333 |