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 | 2 |
| 2 | 14 |
| 3 | 76 |
| 4 | 374 |
| 5 | 1748 |
| 6 | 7916 |
| 7 | 35096 |
| 8 | 153254 |
| 9 | 661636 |
| 10 | 2831300 |
| 11 | 12030632 |
| 12 | 50826684 |
| 13 | 213707336 |
| 14 | 894945944 |
| 15 | 3734901296 |
| 16 | 15540685574 |
| 17 | 64496348516 |
| 18 | 267060529364 |
| 19 | 1103587381256 |
| 20 | 4552196053844 |
| 21 | 18747042089816 |
| 22 | 77092267322984 |
| 23 | 316602500019536 |
| 24 | 1298657603761244 |