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 | 5 |
| 2 | 26 |
| 3 | 146 |
| 4 | 861 |
| 5 | 5229 |
| 6 | 32361 |
| 7 | 202905 |
| 8 | 1284480 |
| 9 | 8191380 |
| 10 | 52543545 |
| 11 | 338641305 |
| 12 | 2191124301 |
| 13 | 14224347181 |
| 14 | 92603307541 |
| 15 | 604342068085 |
| 16 | 3952451061076 |
| 17 | 25898039418496 |
| 18 | 169977746765071 |
| 19 | 1117287239602471 |
| 20 | 7353933943361866 |
| 21 | 48461930821297546 |