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 | 16 |
| 2 | 292 |
| 3 | 2574 |
| 4 | 13344 |
| 5 | 59518 |
| 6 | 250124 |
| 7 | 1024174 |
| 8 | 4143944 |
| 9 | 16671934 |
| 10 | 66886900 |
| 11 | 267965390 |
| 12 | 1072744752 |
| 13 | 4292852990 |
| 14 | 17175392028 |
| 15 | 68710014830 |
| 16 | 274857954776 |
| 17 | 1099469650494 |
| 18 | 4397958390916 |
| 19 | 17592001449102 |
| 20 | 70368358249024 |