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 | 3 |
| 2 | 14 |
| 3 | 70 |
| 4 | 353 |
| 5 | 1782 |
| 6 | 8997 |
| 7 | 45425 |
| 8 | 229347 |
| 9 | 1157954 |
| 10 | 5846414 |
| 11 | 29518061 |
| 12 | 149034250 |
| 13 | 752461609 |
| 14 | 3799116465 |
| 15 | 19181424995 |
| 16 | 96845429254 |
| 17 | 488964567014 |
| 18 | 2468741680809 |
| 19 | 12464472679038 |
| 20 | 62932092237197 |
| 21 | 317738931708801 |