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 | 1 |
| 2 | 26 |
| 3 | 122 |
| 4 | 562 |
| 5 | 3569 |
| 6 | 20088 |
| 7 | 112235 |
| 8 | 643541 |
| 9 | 3666933 |
| 10 | 20890748 |
| 11 | 119144071 |
| 12 | 679253594 |
| 13 | 3873420006 |
| 14 | 22088544036 |
| 15 | 125956423940 |
| 16 | 718274061983 |
| 17 | 4096006211974 |
| 18 | 23357654042928 |
| 19 | 133198547653768 |
| 20 | 759573589408188 |