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 | 5 |
| 2 | 23 |
| 3 | 113 |
| 4 | 619 |
| 5 | 3121 |
| 6 | 15619 |
| 7 | 78121 |
| 8 | 390581 |
| 9 | 1953109 |
| 10 | 9765619 |
| 11 | 48828113 |
| 12 | 244140613 |
| 13 | 1220703073 |
| 14 | 6103515623 |
| 15 | 30517578121 |
| 16 | 152587890563 |
| 17 | 762939453109 |
| 18 | 3814697265523 |
| 19 | 19073486328109 |
| 20 | 95367431640599 |
| 21 | 476837158203071 |
| 22 | 2384185791015571 |
| 23 | 11920928955078089 |