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) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | 6 |
| 5 | 22 |
| 6 | 86 |
| 7 | 335 |
| 8 | 1307 |
| 9 | 5071 |
| 10 | 19664 |
| 11 | 76299 |
| 12 | 296396 |
| 13 | 1152682 |
| 14 | 4487818 |
| 15 | 17492162 |
| 16 | 68252789 |
| 17 | 266589233 |
| 18 | 1042279572 |
| 19 | 4078677195 |
| 20 | 15974343417 |
| 21 | 62614027433 |
| 22 | 245608306154 |
| 23 | 964087953123 |
| 24 | 3786809126547 |
| 25 | 14883181075527 |