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 | 23 |
| 3 | 111 |
| 4 | 479 |
| 5 | 1983 |
| 6 | 8063 |
| 7 | 32511 |
| 8 | 130559 |
| 9 | 523263 |
| 10 | 2095103 |
| 11 | 8384511 |
| 12 | 33546239 |
| 13 | 134201343 |
| 14 | 536838143 |
| 15 | 2147418111 |
| 16 | 8589803519 |
| 17 | 34359476223 |
| 18 | 137438429183 |
| 19 | 549754765311 |
| 20 | 2199021158399 |
| 21 | 8796088827903 |
| 22 | 35184363700223 |
| 23 | 140737471578111 |
| 24 | 562949919866879 |