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 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 13 |
| 5 | 67 |
| 6 | 383 |
| 7 | 2345 |
| 8 | 15069 |
| 9 | 100341 |
| 10 | 686515 |
| 11 | 4797997 |
| 12 | 34110765 |
| 13 | 245926667 |
| 14 | 1793867881 |
| 15 | 13214905229 |
| 16 | 98177212059 |
| 17 | 734746226575 |
| 18 | 5534054981071 |
| 19 | 41917876423855 |
| 20 | 319102504087883 |
| 21 | 2440086947417629 |
| 22 | 18733909260242195 |
| 23 | 144354928765952131 |
| 24 | 1116015033661158079 |
| 25 | 8654019249571514621 |
| 26 | 67292250859412467583 |
| 27 | 524583875375437922949 |