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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 6 |
| 4 | 32 |
| 5 | 162 |
| 6 | 813 |
| 7 | 4068 |
| 8 | 20344 |
| 9 | 101724 |
| 10 | 508625 |
| 11 | 2543130 |
| 12 | 12715656 |
| 13 | 63578286 |
| 14 | 317891437 |
| 15 | 1589457192 |
| 16 | 7947285968 |
| 17 | 39736429848 |
| 18 | 198682149249 |
| 19 | 993410746254 |
| 20 | 4967053731280 |
| 21 | 24835268656410 |
| 22 | 124176343282061 |
| 23 | 620881716410316 |