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 | 7 |
| 2 | 55 |
| 3 | 439 |
| 4 | 3433 |
| 5 | 27541 |
| 6 | 218773 |
| 7 | 1749223 |
| 8 | 13964245 |
| 9 | 111725197 |
| 10 | 893433661 |
| 11 | 7147232467 |
| 12 | 57169672861 |
| 13 | 457364647435 |
| 14 | 3658819119307 |
| 15 | 29270432746633 |
| 16 | 234161501271463 |
| 17 | 1873293863661469 |
| 18 | 14986321908515773 |
| 19 | 119890565631185995 |
| 20 | 959124025074311215 |
| 21 | 7672992332048493361 |