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) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 76 |
| 4 | 475 |
| 5 | 2771 |
| 6 | 16451 |
| 7 | 97160 |
| 8 | 574671 |
| 9 | 3397622 |
| 10 | 20089993 |
| 11 | 118787443 |
| 12 | 702368950 |
| 13 | 4152971123 |
| 14 | 24555730380 |
| 15 | 145193342488 |
| 16 | 858500551625 |
| 17 | 5076149984859 |
| 18 | 30014306641852 |
| 19 | 177468870003729 |
| 20 | 1049339576968817 |