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 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 4 |
| 6 | 3 |
| 7 | 13 |
| 8 | 12 |
| 9 | 39 |
| 10 | 36 |
| 11 | 121 |
| 12 | 116 |
| 13 | 364 |
| 14 | 351 |
| 15 | 1088 |
| 16 | 1080 |
| 17 | 3280 |
| 18 | 3237 |
| 19 | 9841 |
| 20 | 9800 |
| 21 | 29510 |
| 22 | 29403 |
| 23 | 88573 |
| 24 | 88440 |
| 25 | 265716 |
| 26 | 265356 |
| 27 | 797121 |
| 28 | 796796 |
| 29 | 2391484 |
| 30 | 2390352 |
| 31 | 7174453 |
| 32 | 7173360 |
| 33 | 21523238 |
| 34 | 21520080 |
| 35 | 64570064 |
| 36 | 64566684 |
| 37 | 193710244 |
| 38 | 193700403 |
| 39 | 581130368 |
| 40 | 581120880 |