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 | 5 |
| 2 | 26 |
| 3 | 139 |
| 4 | 758 |
| 5 | 4194 |
| 6 | 23460 |
| 7 | 132339 |
| 8 | 751526 |
| 9 | 4290838 |
| 10 | 24607628 |
| 11 | 141648830 |
| 12 | 817952188 |
| 13 | 4736107172 |
| 14 | 27487711752 |
| 15 | 159864676803 |
| 16 | 931448227590 |
| 17 | 5435879858958 |
| 18 | 31769632683132 |
| 19 | 185918669183370 |
| 20 | 1089302293140564 |