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 | 4 |
| 1 | 5 |
| 2 | 9 |
| 3 | 25 |
| 4 | 89 |
| 5 | 345 |
| 6 | 1369 |
| 7 | 5465 |
| 8 | 21849 |
| 9 | 87385 |
| 10 | 349529 |
| 11 | 1398105 |
| 12 | 5592409 |
| 13 | 22369625 |
| 14 | 89478489 |
| 15 | 357913945 |
| 16 | 1431655769 |
| 17 | 5726623065 |
| 18 | 22906492249 |
| 19 | 91625968985 |
| 20 | 366503875929 |
| 21 | 1466015503705 |
| 22 | 5864062014809 |
| 23 | 23456248059225 |
| 24 | 93824992236889 |
| 25 | 375299968947545 |